Abstract: Guide roller of a pair of feed rollers of a granulating device for plastic strands, wherein the guide roller has a core and at least one outer hard rubber layer, wherein the at least one outer hard rubber layer forms a sleeve that can be pushed onto the core of the guide roller and pulled off of the core.

Abstract: A building block is provided with coupling means on the upper and lower faces allow the blocks to be interconnected to form structures. The coupling means includes protrusions on one face and a set of sockets or receptacles sized to engage the protrusions formed on the opposite face. The sockets are preferably laid-out in two cross-like formations of four sockets each and optionally may include a further two central sockets disposed between the two cross-like formations.

Abstract: An inflatable building block is provided with collapsible sides. Coupling means on the upper and lower faces allow the blocks to be interconnected to form structures. A preferred format relies on pleated sides that will collapse in an accordion-like fashion.