( 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.
Some glyphs are synonyms. Parentheses, for example, enclose and separate, like boxes. There are many forms on our keyboards; (), [], {}. Parentheses are naturally interpreted as enclosures as they are arcs of circles facing each other and surrounding the set of things they enclose.
Text turns out to be full of meaningful visual and spatial devices, like parentheses and indentation.
Some glyphs (like some words) are polysemous. A circle can represent an enclosure, a general one, with an unspecified and irrelevant form. But by considering only the perimeter and not the inside, a circle can represent a cycle, a process that goes round and round with no end.
Mind in Motion, by Barbara Tversky
Click on spheres to evaluate the inner expressions and watch them pop!
(((1 + 2) + 3) + 4)
(((1 + 2) + (3 + 4)) + (5 + 6))
(((1 + 2) + (3 + (4 + 5))) + (6 + (7 + 8)))
1. Nested expressions become nested spheres - Each level of parentheses creates a new sphere layer
2. Click to evaluate - When you click a sphere, it evaluates its contents and pops with a satisfying animation
3. Work from the inside out - Start with the innermost spheres and watch the evaluation propagate outward
4. Visual feedback - Popped spheres turn green and display their computed value