The uploaded worksheet animates a cam formed of two Archimedean spirals as the cam rotates, creating vertical motion in a circular cam follower.

DirectSearch is used to locate the centre of the follower, however I experience two problems with this use.

First: DirectSearch places the follower centre sometimes above and sometimes below the cam surface, seemingly at random.

Second: seemingly at random, DirectSearch produces completely wrong values for the follower centre unless its SolveEquations command is executed with the initialpoint values stated in the worksheet. I arrived at these by extensive trial and error.

Why does the first problem occur and is there a way to code SolveEquations to avoid it?

Is there a writeup anywhere which can guide me to correct initialpoint values for a particular SolveEquations attempt?

Archimedian_spiral_cam_follower.mw

Near the top of the large loop at the bottom of the uploaded worksheet IntSect is copied to IntSectRoll.

IntSectRoll is then modified several times within the loop. However IntSect also changes content even though there are no commands within the loop to cause this.

To avoid this is the reason IntSect is recreated from previous data each time before it is copied.

Is this a bug in my worksheet or in Maple 2016?

Constant_Diameter.mw

The theory behind the worksheet is described, without attribution, in the book The Penguin Dictionary of Curious and Interesting Geometry by David G. Wells.

Does this theory have a name and a discoverer?

Plot3d in this worksheet calls a procedure which conditionally returns the values for a parametrically defined ellipsoid, but the plot command fails. However the procedure passes the correct list of parametric values when it is called directly.

Is there a way to call a procedure within plot3d which successfully plots a parametrically defined surface?

Plot3d_proc_parametric.mw

The edges of the red and blue surfaces are ragged. Can they be made smoother when displayed?

Intersecting_surfaces.mw

I would like procedure P to perform inside the map statement exactly as it does outside the map statement. Can this be done?

Map_Procedure.mw