This is the Size 1 Sphinx:

It is made of 6 unit equilateral triangles.
Four of the Size 1 Sphinxes make the Size 2 Sphinx:

And since this new Sphinx demonstrates that four Sphinxes make a Sphinx, then four Size 2 Sphinxes will make another, larger Sphinx which will be Size 4.
Of course it follows that four Size 4 Sphinxes will make a Size 8 and so on.
You might also imagine Size 1 being made from 4 smaller Sphinxes and each of those from 4 smaller Sphinxes and so on!
Further interest is generated by asking:
At this point you could move on to the next link, but without actually struggling with the problem yourself you will not appreciate the significant difference between the Size 4 problem and the Size 3 problem which you might expect to be easier.