Compression adds 6 new compressed blocks, as of v0.3. They are Coal Block, Redstone Block, Slime Block, Dirt Block, Stone Block, and Cobblestone Block. More to come, this is V0.3! They are crafted like this:

XXX
XXX
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X for Coal Block = Coal

X for Redstone Block = Redstone

X for Dirt Block = Dirt

X for Slime Block = Slimeball

X for Stone Block = Stone(Smooth)

X for Cobblestone Block = Cobblestone

INSTALLATION:

Simply drag and drop class files and folder into minecraft.jar. Enjoy!