+ and - keys will change the letter on the material palette square that is selected. The letters are as follows :
// 0 = - GenericSoft
// 1 = S Stone
// 2 = M Metal
// 3 = W Wood
// 4 = G Glass
// 5 = L Liquid Splashy Wet
// 6 = F Flesh (Bloody Organic)
// 7 = H Hollow Drum Metal
// 8 = T Small High Pitch Tin
// 9 = V Small Low Pitch Tin
// 10 = I Silly Material
// 11 = A Marble
// 12 = C Cobble
// 13 = R Gravel
// 14 = E Soft Metal
// 15 = O Old Stone
// 16 = D Old Wood
// 17 = Z Shallow Water
// 18 = U Underwater
Desktop: i7 4770@3.4Ghz (passmark 9809), 12GB RAM, Win 10/64, GeForce GTX 1080 (passmark 12006), 1TB SSD, 1TB HDD; Laptop: i7 4800MQ@2.7Ghz, 16GB RAM, Win 10/64, GeForce GTX870M , 1TB SSD.