Those are Multibus-1 prototyping boards, so they'd be 12"x6.75". It's a good size for building non-trivial things.

I didn't mean to imply that they are abnormal, just that they are large and large boards like that tend to be harder to make stable when using wire wrap as a technique. I've done this - and stacks of them too - but I've also spent days tracing a faulty wire, and the chance of such faults goes up as the number of wires goes up.