Carpenter's Collapsible Block
the collapsible block is a different block from all the others. You place it down, and it is flat.. or so it seems. You can right-click it with the carpenters hammer and it will raise the corner you clicked on by one pixel, and it will make a slope. You can do this up to 16 times. And to put it back down, you can left-click it.
If you place it on the topside of a block, it will turn into an upside-down slope. You can click one of the corners that are extended down and it will fold up, you can do this up to 16 times. and if you want to fold up both corners, it will be flat.. but upside down. And if you want to extend the corners down again, left-click the plate and the corner you clicked on will extend down again.
have fun with this unique and cool block.