how???

@lucasgreer1736 so left and right are 24 and 26 respectively. You get the key and subtract by 25, meaning all that its left is -1 or 1: this will be K (all single numerical variables in ti basic are just single capital letters). D will store direction as an imaginary number you do "KDi->D" so D=K*D*i in most any other language (ti basic lets you write functions as you would in math, anything next to eachother is multiplied). This will basically update what direction you turned in by making it imaginary if its not imaginary or vice versa with K modifying if it becomes negative or not. Then "real(D{4i,6->L1" will basically shove only whatever is real into L1 (a list) leaving the other as zero setting which way you move in the process. Remember i*i=-1. 4 and 6 are there just to tell later code how far horizontal or vertical it should move. Just those two lines after handling the keys alone handle the direction you turn towards. The math just works out

@lucasgreer1736 so the code (omitting a bunch of stuff) is 1->D While 1 repeat Ans ... //the game getkey end ans-25 DiAns->D real(Ans{4i,6->L1 end Firstly lets remember i*i == -1. Secondly TI-BASIC is weird, "->" is how you set variables, with the variable on the right of the arrow being the one set. All normal number variables are single capital letters, you have no choice in their name, A-Z (with exceptions) is all you get. Also it lets you write expressions like you do in math: anything written together is multiplied. "Ans" is a variable that is always the result of the last expression, its technically faster (and smaller since you dont set anything) which is why its written this way. "Repeat" is basically a "do {} while(not(x))" loop if youre familiar with C. It will basically always enter that loop at least once and exit that loop if the thing, in our case the Ans of getkey, isnt zero. You can multiply to all elements of arrays, ex. 2*{3,4} == {6,8} Anyways the meat on "how". Essentially the left and right keys return 24 and 26 respectively, so subtracting 25 will return -1 and 1. "DiAns->D" will therefore return 1, i, -1, and -i, in order if Ans is 1 and 1, -i, -1, and i if Ans is -1 each time it handles the key. Its processed further in "real(Ans{4i,6->L1" to be set in a list that makes any imaginary part of the expression zero, therefore only resulting in one element having a value that isnt zero, separating horizontal from vertical. 4 and 6 are there to tell the program how far to move per cycle horizontally and vertically.

@lucasgreer1736 basically taking advantage of the fact the left and right keys can simply be subtracted by 25 to result in -1 and 1 and that i*i=-1

​@@Palmtop_User Now I want to see the codes.