Catastrophe Puzzle

The Puzzle:

Catastrophe
Draw a circle with radius 5 cm.

Draw a second circle with radius 3 cm just touching the most North-East part of the first circle.

Draw two small triangles, 4 cm apart, resting on top of the second circle.

Inside the second circle, arranged so that they are symmetrical about a vertical line through the centre, draw these four things:
a small triangle at the centre
two small circles 3 cm apart, above the triangle
the bottom half of a circle, below the triangle.

WHAT'S MISSING?
Do you have the answer? Check against our solution!