Interactive Diagrams

Simple envelope created by a moving closet door.
  Click and drag the red hinge point.

View the maximum y-values of three point
on the x-axis: A, B, and C.
Maxima are part of the envelope
Drag hinge point.

View envelope area by tracing the door segment.
Drag hinge point.

View the path of a hypocycloid.
This works for angles between -Pi/4 and Pi/4
Drag point F

Create envelope using Hypocycloid
and closet simultaneously
Drag hinge point.

Watch entire sketchpad construction
generate the envelope.
Drag hinge point.