snow stairs

Changes spruce, and accacia stairs into the snow stairs. Any stairs or any texture that replaces the stairs would work using the same method shown in the resource pack.

!Laminate Floor 02

for example to add more stairs copy same code model/block (3 files for each new stair) then to change texture from snow to other block, change textures\blocks/snow_side.png into other texture but keep the same name.