Spherepop Prototype
( How ( + ( - ( 1 ) ( 2 ) ) ( - ( 1 ) ( 2 ) ) play ) spherepop: ( (Find the ( innermost bubble ) ) and then pop as many ( + b u b b l e s ) ) as you can ( . ) ) )
Spherepop is a visual programming language where nested expressions are represented as nested circles. Clicking on a circle evaluates the inner expression and updates the display.
Basic Principle
( ( ( a + b ) + c ) + d )
For the expression ((a + b) + c) + d, we will have a circle around a + b, a larger circle around (a + b) + c, and a larger circle around ((a + b) + c) + d.
Clicking on a circle will pop it and evaluate the expression within.
Examples:
(((1 + 2) + 3) + 4) → (((3) + 3) + 4)→ (((6) + 4))→ (10)
(((1 + 2) + (3 + 4)) + (5 + 6)) → (((3) + (7)) + (5 + 6)) → (((10)) + (11)) → ((21))→ (21)
((6)÷(2(2+1)))→ ((6)÷(2(3)))→((6)÷(6))→ ((6/6))→((1/1))→((1))→(1)→ 1
Example: (((1 + 2) + 3) + 4)
More Complex Example: (((1 + 2) + (3 + 4)) + (5 + 6))
Even Deeper Example: (((1 + 2) + (3 + (4 + 5))) + (6 + (7 + 8)))
Additional Resources:

Spherepop in Action