So first things first, here's the code

:3->dim(LX)

:3->dim(LY)

:FnOff

:AxesOff

:PlotsOff

:GridOff

:–2.31->Xmin

:.035->∆X

:–1.085->Ymin

:∆X->∆Y

:Input "STAGE(≥4):",K

:If K<4:4->K

:Disp "MOMENT PLEASE.."

:ClrDraw

:0->T:3->N

:0.24->LX(N)

:0->LY(N)

:

:Lbl F

:1->Z:Goto M

:

:Lbl 1

:If T=0:Then

:LX(N)+∆X->LX(N)

:Goto F

:End

:

:1->J:2->P

:LX(N)-∆X->LX(J)

:LX(N)->LX(P)

:LY(N)->LY(J)

:LY(N)->LY(P)

:LY(N)+∆Y->LY(N)

:Pt-On(LX(J),LY(J))

:

:LX(J)->U

:LY(J)->V

:LX(P)->W

:LY(P)->A

:

:2->Z

:

:Lbl S

:Goto M

:

:Lbl 2

:If T=0

:Then

:Pt-On(LX(N),LY(N))

:Pt-On(LX(N),–LY(N))

:J->R:N->J

:Else

:P->R:N->P

:End

:R->N

:LX(J)+LX(P)-LX(R)->LX(N)

:LY(J)+LY(P)-LY(R)->LY(N)

:If LY(N)≥0:Goto S

:

:Lbl Q

:Text(0,0,K)

:Stop

:

:Lbl M

:LX(N)->X

:LY(N)->Y

:0->T

:If X<Xmin or X>Xmax or Y<Ymin or Y>Ymax

:1->T

:1->I

:While I<K and T=0

:I+1->I

:X¯->Q:Y¯->S

:If Q+S>5

:Then

:1->T

:Else

:2XY+LY(N)->Y

:Q-S+LX(N)->X

:End

:End

:If Z=1:Goto 1

:If Z=2:Goto 2

Every other part is fine, but the part that's throwing me off is this: X¯->Q:Y¯->S. Those X and Y symbols do not exist on a ti 83 plus. I've tried substituting several possibilities, such as Xbar and Ybar, X^-1 and Y^-1, and just X and Y. I'm at a loss as to what to do, so any assistance at all would be appreciated. Thanks.