Source
What the programme prints. It runs twice, once by the interpreter and once as compiled Python, and the line at the top right says whether both printed the same thing.
The type of every top-level definition, worked out by the compiler. 'a means any type.
Where each name can be used. Each line is a part of the programme that opens a scope, with the names it introduces there. Click a line to find it in the source.
The same programme, translated into Python by the compiler.
Your programme, written back out from the tree the compiler built. A bracket you did not write shows how it grouped your code.
The run, one evaluation at a time. Yellow marks the expression about to be evaluated, green one that has just produced its value.