Hold onto your pants.

°S→A
8
While 1
End!If Select(-1,Select({+S},*2/10Store())^5Store())

Lbl Store
→{A-2→A}ʳ
Return

If speed is important and you want to avoid the /10 B_CALL and doing both a divide and a modulus operation:

°S→A
8
While 1
End!If Select(-1,{+S}-(Select(/5,Store())*5)Store())

Lbl Store
→{A-2→A}ʳ
Return


EDIT: I do hope these actually work; I didn't test them.

EDIT 2: Now I did test them, fixed a small issue with the second one and now they both work.

Select(EXPR1,EXPR2) is an optimized way (only 2 bytes!) of saving the value of EXPR1, then evaluating EXPR2, then restoring the value of EXPR1. The first Select(-1,blah) decrements one from the loop counter, which goes from 3 to 0, and then saves it while we do the actual work. The next Select({+S},blah) adds the loop counter to S, reads the value at that memory location, and saves it; this is so we can use it for the ^5 later, while we can also use it for *2/10 now. Each call to the Store() command stores the 2-byte value before it to the previous letter variable (starting with S/R), and because of how we ordered our calls to it, we store the value divided by 5 first to the later letter variable, and then the value modulo 5 second to the letter variable right before it.

Yes, it is a minus sign, like in 1-1=0. About your error, are you sure you put the "," after the "-1" ?

It seems to work fine when I run it; given Data(18,24,16,9,6,8,15,19)→S, I get:

• C: 3
• D: 3
• E: 4
• F: 4
• G: 1
• H: 3
• I: 4
• J: 1
• K: 1
• L: 1
• M: 3
• N: 1
• O: 0
• P: 3
• Q: 4
• R: 3

Are you sure you copied the code correctly? I can understand copying it incorrectly because the code is a little strange.

Yeah, should've got a camera... Anyways, I had the second one copied; I tried Runner's 1st code and it worked. Thanks for the help!

Ok, I have another thing I need to optimize. (idk why I named the topic var locations, the solution had nothing to do with that, and it really is just for optimizations that I can't do)
Pt-On(C*9+1,D*9+1,Pic1)
Pt-On(E*9+1,F*9+1,Pic1)
Pt-On(G*9+1,H*9+1,Pic2)
Pt-On(I*9+1,J*9+1,Pic2)
Pt-On(K*9+1,L*9+1,Pic3)
Pt-On(M*9+1,N*9+1,Pic3)
Pt-On(O*9+1,P*9+1,Pic4)
Pt-On(Q*9+1,R*9+1,Pic4)
I defined Pic1-Pic4 like this:
[stuff]->Pic1
[stuff]
[stuff]->Pic2
[stuff]
[stuff]->Pic3
[stuff]
[stuff]->Pic4
[stuff]