Incremental skins

I shall try to explain here the concept of incremental skins present
in myrpl magic creator.

The basic idea is that a skin could modify either all or part of a previous
skin

Suppose that when you load the calculator you see a skin named skin zero

You could load a new skin named , for example, skin one.
This skin modifies parts of skin zero.

Then , you load another skin, for example, skin two. 
This skin modifies the result of skin 0 + skin 1

Now, if you load another skin, for example, skin three,
this skin changes things present on the result of mixing
skin 0 + skin 1 + skin 2.

So, you could load a train of skins , each new skin is applied over the mix
of all previous skins.