So for my TI-Concours BASIC (z80) entry, you can see what it looks like below. We were supposed to make Mastermind, so I put the core of it together with a custom graphscreen input routine. I made it return smileys for correct numbers and positions, ? for correct numbers, bad positions, and an X for numbers not in the code. Then I made sure that the maximum number of allowed turns was 12 and I decided to make a fancy-ish main menu. It draws three main objects in random locations every setup and I made sure it wouldn't interfere with the menu. What is more, my program doesn't tamper with window settings, so even if you press ON, your window settings are preserved as well as Axes, Grid, and the like. The only thing the program modifies is it turns off the graphs and plots.