Idea

Idea is an esoteric programming language that provides only 4 symbols, making it both very hard to read and write in.

Instructions

—=Start/end selection
→=move right
←=move left

Press → and at end of line: evaluate selected text as Idea expression, supports recursion. It will not evaluate a null text.

Press ← and at beginning of line: escape the next character into the file.

All characters that are not these three instructions are preserved in the next evaluation. They do nothing.

Just one recursion

a←—→—→

Two recursions(and so on)

To create more recursions, put this into the editing area and evaluate it.

←→←←—←←→←←—←←←←a←—→→→→→→—→