A Little Challenge: Spin the Circle

[SMcNeill]

For i = start To fini Step Sgn(fini - start)

Start = 1: Fini = 90
SGN(90 - 1) = +1 'It's a positive number, so what we end up with is:

FOR i = 1 TO 90 STEP 1

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Now, swap start and fini

Start = 90: Fini = 1
SGN (1 -90) = SGN (-89) = -1 it's a negative number, so we end up with:

FOR I = 90 TO 1 STEP -1

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See the logic here?