diff --git a/pom.xml b/pom.xml
index 6748faf..2f09960 100644
--- a/pom.xml
+++ b/pom.xml
@@ -4,7 +4,7 @@
 
     <groupId>com.marginallyclever</groupId>
     <artifactId>nodegraphcore</artifactId>
-    <version>1.6.1</version>
+    <version>1.6.2</version>
 
     <name>NodeGraphCore</name>
     <description>Flow based programming in Java.</description>
@@ -57,7 +57,7 @@
         <dependency>
             <groupId>org.json</groupId>
             <artifactId>json</artifactId>
-            <version>20231013</version>
+            <version>20250517</version>
         </dependency>
         <!-- unit testing -->
         <dependency>
@@ -74,24 +74,20 @@
             <scope>test</scope>
         </dependency>
         <!-- for logging -->
-        <!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-api -->
         <dependency>
             <groupId>org.slf4j</groupId>
             <artifactId>slf4j-api</artifactId>
-            <version>2.0.16</version>
+            <version>2.0.17</version>
+        </dependency>
+        <dependency>
+            <groupId>ch.qos.logback</groupId>
+            <artifactId>logback-core</artifactId>
+            <version>1.5.18</version>
         </dependency>
-        <!-- logging -->
         <dependency>
             <groupId>ch.qos.logback</groupId>
             <artifactId>logback-classic</artifactId>
-            <version>1.5.16</version>
-            <scope>test</scope>
-            <exclusions>
-                <exclusion>
-                    <groupId>org.slf4j</groupId>
-                    <artifactId>slf4j-api</artifactId>
-                </exclusion>
-            </exclusions>
+            <version>1.5.18</version>
         </dependency>
         <!-- for finding nodes in a package -->
         <dependency>
diff --git a/src/main/java/com/marginallyclever/nodegraphcore/Node.java b/src/main/java/com/marginallyclever/nodegraphcore/Node.java
index 44b0506..a691e35 100644
--- a/src/main/java/com/marginallyclever/nodegraphcore/Node.java
+++ b/src/main/java/com/marginallyclever/nodegraphcore/Node.java
@@ -9,9 +9,11 @@
 import org.json.JSONObject;
 
 import javax.annotation.Nonnull;
+import javax.swing.*;
 import java.awt.*;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Objects;
 import java.util.UUID;
 import java.util.concurrent.atomic.AtomicInteger;
 
@@ -167,13 +169,25 @@ public Port<?> getPort(int index) throws IndexOutOfBoundsException {
      * @param name the name to match.
      * @return the {@link Port} found or null
      */
-    public Port<?> getPort(String name) {
+    public Port<?> getPort(@Nonnull String name) {
         for(Port<?> v : ports) {
             if(v.getName().equals(name)) return v;
         }
         return null;
     }
 
+    /**
+     * Get the {@link Port} with the given name and set its value.
+     * @param name the {@link Port} name to match.
+     * @param value the new value to set.
+     * @throws IllegalArgumentException when the {@link Port} is not found.
+     */
+    public void setPort(@Nonnull String name, Object value) {
+        var port = getPort(name);
+        if(port == null) throw new IllegalArgumentException("Port "+name+" not found");
+        port.setValue(value);
+    }
+
     /**
      * @param name the {@link Port} name to match.
      * @return the index of the {@link Port} with the given name or -1 if not found.
@@ -401,4 +415,12 @@ public int getComplete() {
     public void setComplete(int percent) {
         this.complete.set(percent);
     }
+
+    /**
+     * Returns an icon for this node.
+     * @return an icon for this node or null if no icon is defined.
+     */
+    public Icon getIcon() {
+        return new ImageIcon(Objects.requireNonNull(getClass().getResource("icons8-question-mark-16.png")));
+    }
 }
diff --git a/src/main/java/com/marginallyclever/nodegraphcore/NodeCategory.java b/src/main/java/com/marginallyclever/nodegraphcore/NodeCategory.java
index 746f1f1..ec6bb73 100644
--- a/src/main/java/com/marginallyclever/nodegraphcore/NodeCategory.java
+++ b/src/main/java/com/marginallyclever/nodegraphcore/NodeCategory.java
@@ -4,6 +4,11 @@
 import java.util.List;
 import java.util.function.Supplier;
 
+/**
+ * A category of {@link Node} that can be used to organize nodes into a tree structure.
+ * Each category can have a parent and children, allowing for hierarchical organization.
+ * Categories can also provide a supplier to create instances of the node type they represent.
+ */
 public class NodeCategory {
     private final String name;
     private final Supplier<Node> supplier;
diff --git a/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/ATan2.java b/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/ATan2.java
index 6decc3f..2aa06d2 100644
--- a/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/ATan2.java
+++ b/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/ATan2.java
@@ -4,6 +4,9 @@
 import com.marginallyclever.nodegraphcore.port.Input;
 import com.marginallyclever.nodegraphcore.port.Output;
 
+import javax.swing.*;
+import java.util.Objects;
+
 /**
  * C=atan2(y,x)
  * @author Dan Royer
@@ -30,4 +33,9 @@ public void update() {
         double x = b.getValue().doubleValue();
         c.setValue(Math.atan2(y,x));
     }
+
+    @Override
+    public Icon getIcon() {
+        return new ImageIcon(Objects.requireNonNull(getClass().getResource("tan-curve-16.png")));
+    }
 }
diff --git a/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/Add.java b/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/Add.java
index 9bb48ba..28cebd7 100644
--- a/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/Add.java
+++ b/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/Add.java
@@ -4,6 +4,9 @@
 import com.marginallyclever.nodegraphcore.port.Input;
 import com.marginallyclever.nodegraphcore.port.Output;
 
+import javax.swing.*;
+import java.util.Objects;
+
 /**
  * C=A+B
  * @author Dan Royer
@@ -30,4 +33,9 @@ public void update() {
         double bv = b.getValue().doubleValue();
         c.setValue(av + bv);
     }
+
+    @Override
+    public Icon getIcon() {
+        return new ImageIcon(Objects.requireNonNull(getClass().getResource("icons8-add-16.png")));
+    }
 }
diff --git a/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/Divide.java b/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/Divide.java
index e5359da..566c8a8 100644
--- a/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/Divide.java
+++ b/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/Divide.java
@@ -4,6 +4,9 @@
 import com.marginallyclever.nodegraphcore.port.Input;
 import com.marginallyclever.nodegraphcore.port.Output;
 
+import javax.swing.*;
+import java.util.Objects;
+
 /**
  * C=A/B
  */
@@ -29,4 +32,9 @@ public void update() {
         if(bv==0) c.setValue(Float.NaN);
         else c.setValue(av / bv);
     }
+
+    @Override
+    public Icon getIcon() {
+        return new ImageIcon(Objects.requireNonNull(getClass().getResource("icons8-divide-16.png")));
+    }
 }
diff --git a/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/Equals.java b/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/Equals.java
index dcf20bd..8a3eabe 100644
--- a/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/Equals.java
+++ b/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/Equals.java
@@ -4,6 +4,9 @@
 import com.marginallyclever.nodegraphcore.port.Input;
 import com.marginallyclever.nodegraphcore.port.Output;
 
+import javax.swing.*;
+import java.util.Objects;
+
 /**
  * C = (A==B) ? 1 : 0
  * @author Dan Royer
@@ -30,4 +33,9 @@ public void update() {
         double bv = b.getValue().doubleValue();
         c.setValue((av == bv) ? 1 : 0);
     }
+
+    @Override
+    public Icon getIcon() {
+        return new ImageIcon(Objects.requireNonNull(getClass().getResource("icons8-equal-sign-16.png")));
+    }
 }
diff --git a/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/GreaterThan.java b/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/GreaterThan.java
index 9100d1e..cd9b985 100644
--- a/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/GreaterThan.java
+++ b/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/GreaterThan.java
@@ -4,6 +4,9 @@
 import com.marginallyclever.nodegraphcore.port.Input;
 import com.marginallyclever.nodegraphcore.port.Output;
 
+import javax.swing.*;
+import java.util.Objects;
+
 /**
  * C = (A&gt;B) ? 1 : 0
  * @author Dan Royer
@@ -30,4 +33,9 @@ public void update() {
         double bv = b.getValue().doubleValue();
         c.setValue((av > bv) ? 1 : 0);
     }
+
+    @Override
+    public Icon getIcon() {
+        return new ImageIcon(Objects.requireNonNull(getClass().getResource("icons8-more-than-16.png")));
+    }
 }
diff --git a/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/LessThan.java b/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/LessThan.java
index fbc0056..e4c4bef 100644
--- a/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/LessThan.java
+++ b/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/LessThan.java
@@ -4,6 +4,9 @@
 import com.marginallyclever.nodegraphcore.port.Input;
 import com.marginallyclever.nodegraphcore.port.Output;
 
+import javax.swing.*;
+import java.util.Objects;
+
 /**
  * C = (A&lt;B) ? 1 : 0
  * @author Dan Royer
@@ -30,4 +33,9 @@ public void update() {
         double bv = b.getValue().doubleValue();
         c.setValue((av < bv) ? 1 : 0);
     }
+
+    @Override
+    public Icon getIcon() {
+        return new ImageIcon(Objects.requireNonNull(getClass().getResource("icons8-less-than-16.png")));
+    }
 }
diff --git a/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/Multiply.java b/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/Multiply.java
index 8004114..f7ce525 100644
--- a/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/Multiply.java
+++ b/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/Multiply.java
@@ -4,6 +4,9 @@
 import com.marginallyclever.nodegraphcore.port.Input;
 import com.marginallyclever.nodegraphcore.port.Output;
 
+import javax.swing.*;
+import java.util.Objects;
+
 /**
  * A*B {@link Node}
  */
@@ -28,4 +31,9 @@ public void update() {
         double bv = b.getValue().doubleValue();
         c.setValue(av * bv);
     }
+
+    @Override
+    public Icon getIcon() {
+        return new ImageIcon(Objects.requireNonNull(getClass().getResource("icons8-multiply-16.png")));
+    }
 }
diff --git a/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/Subtract.java b/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/Subtract.java
index a9e9741..019bd26 100644
--- a/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/Subtract.java
+++ b/src/main/java/com/marginallyclever/nodegraphcore/nodes/math/Subtract.java
@@ -4,6 +4,9 @@
 import com.marginallyclever.nodegraphcore.port.Input;
 import com.marginallyclever.nodegraphcore.port.Output;
 
+import javax.swing.*;
+import java.util.Objects;
+
 /**
  * A-B {@link Node}
  */
@@ -28,4 +31,9 @@ public void update() {
         double bv = b.getValue().doubleValue();
         c.setValue(av - bv);
     }
+
+    @Override
+    public Icon getIcon() {
+        return new ImageIcon(Objects.requireNonNull(getClass().getResource("icons8-subtract-16.png")));
+    }
 }
diff --git a/src/main/resources/com/marginallyclever/nodegraphcore/.placeholder b/src/main/resources/com/marginallyclever/nodegraphcore/.placeholder
new file mode 100644
index 0000000..e69de29
diff --git a/src/main/resources/com/marginallyclever/nodegraphcore/icons8-question-mark-16.png b/src/main/resources/com/marginallyclever/nodegraphcore/icons8-question-mark-16.png
new file mode 100644
index 0000000..832d94a
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diff --git a/src/main/resources/com/marginallyclever/nodegraphcore/nodes/math/icons8-add-16.png b/src/main/resources/com/marginallyclever/nodegraphcore/nodes/math/icons8-add-16.png
new file mode 100644
index 0000000..7559623
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diff --git a/src/main/resources/com/marginallyclever/nodegraphcore/nodes/math/icons8-divide-16.png b/src/main/resources/com/marginallyclever/nodegraphcore/nodes/math/icons8-divide-16.png
new file mode 100644
index 0000000..79f7057
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diff --git a/src/main/resources/com/marginallyclever/nodegraphcore/nodes/math/icons8-equal-sign-16.png b/src/main/resources/com/marginallyclever/nodegraphcore/nodes/math/icons8-equal-sign-16.png
new file mode 100644
index 0000000..163fcd9
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diff --git a/src/main/resources/com/marginallyclever/nodegraphcore/nodes/math/icons8-less-or-equal-16.png b/src/main/resources/com/marginallyclever/nodegraphcore/nodes/math/icons8-less-or-equal-16.png
new file mode 100644
index 0000000..f8dea5e
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diff --git a/src/main/resources/com/marginallyclever/nodegraphcore/nodes/math/icons8-less-than-16.png b/src/main/resources/com/marginallyclever/nodegraphcore/nodes/math/icons8-less-than-16.png
new file mode 100644
index 0000000..ff2247c
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diff --git a/src/main/resources/com/marginallyclever/nodegraphcore/nodes/math/icons8-more-or-equal-16.png b/src/main/resources/com/marginallyclever/nodegraphcore/nodes/math/icons8-more-or-equal-16.png
new file mode 100644
index 0000000..0fe6f63
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diff --git a/src/main/resources/com/marginallyclever/nodegraphcore/nodes/math/icons8-more-than-16.png b/src/main/resources/com/marginallyclever/nodegraphcore/nodes/math/icons8-more-than-16.png
new file mode 100644
index 0000000..c98902e
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diff --git a/src/main/resources/com/marginallyclever/nodegraphcore/nodes/math/icons8-multiply-16.png b/src/main/resources/com/marginallyclever/nodegraphcore/nodes/math/icons8-multiply-16.png
new file mode 100644
index 0000000..a45b772
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diff --git a/src/main/resources/com/marginallyclever/nodegraphcore/nodes/math/icons8-subtract-16.png b/src/main/resources/com/marginallyclever/nodegraphcore/nodes/math/icons8-subtract-16.png
new file mode 100644
index 0000000..c8918b0
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diff --git a/src/main/resources/com/marginallyclever/nodegraphcore/nodes/math/tan_curve-16.ico b/src/main/resources/com/marginallyclever/nodegraphcore/nodes/math/tan_curve-16.ico
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index 0000000..fda169d
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