Chain of Changes

Here is a set of shapes:

What do you see?
What do you notice?

If possible, talk to somone else about your noticings.

In this problem, we are going to arrange shapes in a line, in a particular order.
You may like to print and cut out a set of shapes from this sheet, or you could try out your ideas using the interactivity below.

Your challenge, as you add a shape to your line, is to change first colour, then shape, then colour again, then shape and so on. (Or first shape then colour...)

For example, if you put the yellow triangle after the blue one and so change the colour, next you must put another yellow piece and so change the shape.

To help you get the idea, below there are two pictures. Each picture shows the first four shapes of a sequence. 
Which sequence follows the rule and which does not? How do you know?

Sequence 1:	...
Sequence 2:	...

Have a go at creating your own sequence of shapes which follows the rule of changing first colour, then shape, then colour... (Or first shape, then colour...)
How many shapes did you use?
Have another go. How many shapes did you use this time?
Is it possible to use more shapes, still following this pattern?
Can you use all the shapes in this way? Why or why not?