SP4CEBAR 2023-12-22 23:28 (Edited)
Use the gamepad's joystick to move around and the buttons to change the graph.
You can edit the graph subprogram in the source code to add your own graphs, discrete, recursive (aka differential), and parametric graphs are supported.
Update 1: parametric graphs
Update 2: gamepad controls
Update 3: bug fixed: X was allowed to be in the range of 0 to 159 when writing to the character registers (at $8000) which made it overflow into the BG 0 registers right after (at $9000). Now X is in the range of 0 to 127.