Running out of sharp corners when erasing?

A small problem but yet an inefficient one and one for which there is a well-designed solution as rounded corners simply aren't as accurate, and don't seem to erase as well.

The Kadokeshi 28-Corner eraser with its unique shape means that it has a greater number of corners than a conventional eraser, whilst using no extra space.

Once a block of corners is blunted, the block can be pulled off to give access to the next sharp corner.

The Numbers:

Eraser measures approx. 50mm long, 20mm wide.