Snapshot sequence

Hi guys, having problems understand what exactly this means :

Write a snapshot sequence for the computation 12 mod 5 of the following
algorithm

MOD
Input: a non-negative integer a and a positive integer b
Output: the remainder when a is divided by b

1. while a is greater than or equal to b
2. replace a with a - b
3. return a

The first snapshot is
(1. a = 12, b = 5)

I'm not too sure what a snapshot sequence is, hopefully I can get some help with this question guys

Can you ask whoever wrote that description what a "snapshot sequence" is?
I've never heard of it.

The lecturer has posted it on the course website and as a question for an assignment. I have sent him 3 e-mails over the course of the last month he has still not replied