(Image source is the Soviet Calculators History page.)

Yes, yes it is. Here’s one the human race made earlier. This is a Russian abacus. See how the beads are coloured. It means the quantity can be appraised by looking, rather than counting.

This is a case of voluntary attention. Now let’s talk about focus, and involuntary attention.

Matt Webb, S&W, posted 2006-04-13 (talk on 2006-02-08)