Strange 2x2 Inverted slope with hollow center Identification I have a brick that is similar to a 45 degree inverted slope 2x2 except where the un-sloped flat face should be there is a rectangular cavity into the brick

   _______
  /   ____|
 /   |
/     ----|
--HH---HH-


that is a rough cross-section of what it looks like where the H's represent the studs on the bottom
Could be one of the bricks used at section 7 and 9 of this Tyco Super Blocks set:



Source: http://bricker.ru/instructions/download/Tyco%20Super%20Blocks/5281-2.pdf