Chunk coords

[ShadowCone]

Assuming chunk 0,0 is from 0,0 to 15,15

Then chunk 1,0 would be from 16,0 to 31,15

And chunk n,m would be at n*16,m*16 to n*16+15,m*16+15

So actually you multiply by 16 to get the begin and add 15 to the begin to get the last one.