Topology Sketchpad

Draw points, curves, and open sets.

How to Use

Use modes to:

• Sketch open discs
• Sketch general open sets (blobs)
• Sketch curves
• Place points
• Shift objects and labels
• Adjust shapes of blobs and curves

We can also compute set areas, curve lengths, intersections, unions, and more. Draw a set to see its area computed below.

Area of newest set: n/a