If i wanted to make a block with a different shape. Can i? and if so, how?

the shape of a block must be a single cuboid

in mcgalaxy:

/[lb command] edit [block id] min [min coords]
/[lb command] edit [block id] max [max coords]

the command is /os lb if you're editing the blocks in your level, /lb if you're editing the blocks in the level but it's not yours or /gb if you're editing blocks for the whole server

in singleplayer (in recent versions of cc):

/blockedit [block id] min [min coords]
/blockedit [block id] max [max coords]

the min and max coords are 3 numbers from 0 to 16

for example to make a torch (assuming you set the textures correctly):

/[lb command] edit [block id] min 7 0 7
/[lb command] edit [block id] max 9 10 9

to make a slab:

/[lb command] edit [block id] min 0 0 0
/[lb command] edit [block id] max 16 8 16