[TI-84Evo] Spirographing v1.0
by Christopher "Kerm Martian" Mitchell, Ph.D.
Released August 20, 2014 for TI-84 Plus CSE
Released May 14, 2026 for TI-84 Evo
https://z80.me
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Requirements: TI-84 Evo or TI-84 Evo-T

Installation: Send SPROGRPH (SPROGRPH.8xp2) to your calculator. Run
              prgmSPROGRPH from the homescreen via the [PRGM] key.

Keys: 
    --Main Menu--
      [F1]-[F5] ([Y=]-[GRAPH]) for menus
      [CLEAR} to quit program

    --Sub-menus--
      [<][>][v][^] to navigate
      [ENTER] to select item or close menu
      [CLEAR] to quit program

This edutaining program lets you graph curves of the kind created by
the popular "Spirograph" toy. In math terms, it produces parametric
curves in the epicycloid and hypocycloid families. The equations used
to produce the curves are shown here:

               Tr           Tr
X1T = (R-r)cos(--)+Acos(T - --)
               R            R

               Tr           Tr
Y1T = (R-r)sin(--)+Asin(T - --)
               R            R

The user controls the value of R, r (TI variable S), and A. The user
also specifies the number of revolutions (used to compute the value
of Tmax). This program includes six demo curves, and you can modify
the parameters of any of the demos to experiment with your own designs.
A great way for students to see the connection between math and art!

Info: https://www.cemetech.net