# TT1 Dissections

### Author : Gavin Theobald

TT1 dissections are created using two T strips. As for PT dissections there
are limits on how we place the strips, but TT1 dissections are much
more restrictive. Each strip must be placed so that its edges pass through
the anchor points of the other strip. This means that there are only eight
possible ways of combining the strips. If the strip elements have lines of
symmetry, then there may be even fewer combinations.

We now look at an example by dissecting a triangle to a pentagon:

The strips are overlaid. Note how the edges of the triangle strip
pass through the red anchor points of the pentagon strip and the edges
of the pentagon strip pass through the red anchor points of the triangle strip.
This causes the blue intermediate anchor points to coincide.

This gives the following dissection:

There are no more examples of TT1 dissections. This form of dissection
is very rarely useful but is explained for the sake of completeness. We
are now ready to look at the much more useful TT2 dissection method.