After looking at this problem I noticed that there are 8 Sr, 8 Lux, 8 Br which =24 on a 36 square grid. I added 7 Sr, 4 Lux, 1 Br, to the 36 square grid in that order, which did not work (see above)...so I changed the order in which they appear on the 36 square grid, 15 Sr followed by 12 Lux...