I still don't get why this recipe creates a score impact, although it only outputs some text to show how the function works and doesn't do any changes on the puzzle itself.
If you know why, tell me, please.

Note that this function intendedly doesn't work symmetric (similar to the sinus-function, which also isn't symmetric at the y-axis) to keep the "waveform" homogenous on the x-axis.
If you want a symmetric output, use absolute values as function-input.

function Sawtooth(x,range) -- returns values between only 1 and range
x2=x
if x2>0 then
x2=((x2-1)%range)+1
else
x2=range-(-x2%range)
end
return x2
end

for k=15,-15,-1 do
l=Sawtooth(k,10)
print (k," ",l)
end