12.4 Recursive macros

Besides being useful for often-used constructions macros can be used to achieve things that would not be possible ’by hand’. Letīs assume you want to construct a staircase. A rectangular surface should be given (by its four vertices), then you construct one step of the staircase:


I will not give the details of this construction here; you should be able to figure it out yourself if you want to use recursive macros.

Now the recursion:

Now you can save the macro (i.e. ’stair.geosave’). You can call up the macro if you select the upper four points of the scene and use ’Macro-play’.

Choose ten recursions and you get:


You can even use more than one recursion. This way it is possible to construct a surface-fractal like this one:


12.4.1 Defining and deleting recursions