several sky-floors in one pwad

perhaps i have got tomatoes on my eyes
but i just found 1 skyfloor in my DOOM2.WAD!
and it is very boooooooooooring!

is it able to put several sky-floors in one pwad
and how is it done????

Do you mean sky textures? In regular DOOM, you can only have one sky texture for an episode.

In the newer source ports, you can have one sky per level, or in some cases, as many skies as you want in a single level (EDGE can change sky textures on the fly using RTS).