Light isn't important, but sequence is a key word, think about what properties the various shapes have.

Look at the number of sides each shape has. Is there a pattern? Which would come next in the sequence?

to assume the numbers were part of the problem, when they are in fact just the order the shapes go in... Doh is I think the appropriate comment...

1,1,2,3,5,8? do i just add them together to make the sequence, eg 5+8=13?

'sequence' is important, maybe a particularly well known one