Here's the line. Type it into your calculator and see if you can fix it!
Output(10,R,"]")
Output(10,R+W,"[")
Here is the full code if you need that too.
ClrHome
Disp ""
Disp " READY, SET,"
Disp " 3"
Disp " 2"
Disp " 1"
Disp ""
For(X,1,500):End
Disp " GO!"
Disp "":Disp "":Disp ""
0→D:0→C:13→X:8→W
int((28-W-1)/2)→R
{R,R,R,R}→L₁
0→S:8→M:0→N
While D=0
Output(10,R,"]")
Output(10,R+W,"[")
Disp "":Output(2,1,C)
Output(6,X,"=V=")
Output(5,X,"O+O")
Output(4,X," 0 ")
Output(3,X,"O^O")
Output(2,X," ")
If X≥L₁(1) and X≤L₁(1)+W-2:Then
N+1→N:If N=M:Then
If R=9:Then
randInt(1,1)→S
Else
round((R-9)/W,0)*randInt(1,0)→S
End
0→N
End
R+S→R
seq(L₁(I),I,2,4)→L₁
R→L₁(4)
C+1→C
getKey→K
If K=24:Then
Output(3,X+2," ")
Output(4,X+2," ")
Output(5,X+2," ")
Output(6,X+2," ")
X-1+(X=1)→X:Else:If K=26
Then
Output(3,X," ")
Output(4,X," ")
Output(5,X," ")
Output(6,X," ")
X+1-(X=24)→X:End:End
Else:1→D:End
End