@Kitonum Entering command interface(version) produced this response:

Standard Worksheet Interface, Maple 15.01, Windows NT (unknown), June 2 2011 Build ID 636299

Could there be a bug in this version of Maple 15?

My operating system is Windows 10. I intend to upgrade to Maple 2016 as soon as it is available.

@Markiyan Hirnyk I emailed WPI several days ago and have received no reply.

@Markiyan Hirnyk Are you aware of any other source describing the commands in package CalcP7, or of any other package providing the same sort of functionality?

@Markiyan Hirnyk I have the 64-bit version, Windows 10 version 1511, build 10586.71 installed about 2 months ago.

I intend to upgrade to Maple 2016 when it is released. Do you know when this will happen?

BTW I have also downloaded the package InequalityGraphics which produces some interesting displays. No help pages appear for this package but issuing either of its two commands with no parameters displays a list of that command's parameters.

@Markiyan Hirnyk I have Maple 15 running under Windows 10. I followed the installation instructions in this website

https://www.wpi.edu/academics/math/calcp7.html

@Kitonum Thank you for your explanation. I have a better understanding now.

@Preben Alsholm 

@Kitonum I failed to notice that x had previously been assigned a value and thereafter must appear unevaluated. Interestingly, the spacecurve command did not issue an error message.

@vv Thank you for another clear explanation and for the New Year's wishes. All the best to you and your family in 2016 and I look forward to more crystal math education from you.

@vv What clever reasoning; the minimum x after any rotation and translation of the ellipse in the corner. This reasoning should apply to any other ellipse-like shape in a corner.

@vv I understand your parametric expressions for the coordinates of the sliding ellipse (Wikipedia helps) but

I must be thick as I've tried and failed to derive the coordinates of xc and yc. Please explain how their expressions arise (a diagram of the ellipse rotated at a sample angle would help).

@vv Does the expression you plot for the sliding ellipse presume that its centre moves in a circle whose centre is the origin?

@Markiyan Hirnyk I forgot to make clear that I have no clue how to prove the path of the sliding ellipse's centre is an arc of a circle.

The first worksheet animates the ellipse sliding against stationary axes , the second animates the axes sliding against the stationary ellipse. The first worksheet uses the technique in the second worksheet. Both are written in Maple15.

MathMech_ellipse_sliding_in_first_quadrant_pg_72.mw

MathMech_tangents_sliding_around_ellipse.mw

Page 72 refers to the book "The Mathematical Mechanic" by Mark Levi, Princeton University Press. This is where I first learned of this problem.

@vv The Alexander horned sphere is one of the wierdest objects I've encountered!

@Kitonum I apologize for not previously thanking you for your correct answer to my question.

It seems that Maple15 cannot display a truly solid object. For example, when I display a hemisphere and ask that the region between it and the xy plane be filled, the projection of the hemisphere on the plane is coloured but the interior of the figure is hollow, as evidenced if you bore a hole through it. Am I correct in this?. Is there a way to display an enclosed 3D figure, such as a sphere, with a fully coloured interior?