MReserveShapes [(]NumberOfShapes.w[,ShapeBankToUse.w][)] ; Reserve structure-memory for Shapes

This must be called before any operations are performed that have anything to do
with chunky Shape objects, unless making use of the default reserved chunky
Shapes. A chunky Shape is one of Mildred's `shape' objects, akin to a normal
blitz shapes except that they hold different information and the graphics are
stored in a different format (chunky). Using this command does not allocate
space for any shape graphics, but does make space for the shapes to be created
and stored. Chunky Shapes are numbered from 0 upwards. If used as a function,
this command will return the address of where the chunky Shape objects
(structures) are being stored, or 0 for failure. If the optional
ShapeBankToUse parameter is specified, with a valid shape bank number in the
range 0..31, a particular bank will be `used' before new space for chunky Shapes
is allocated, meaning that you do not have to perform a seperate call to
MUseShapeBank.