Beat 1 · Concrete
Find a way through
A solver tries routes from start toward the goal, backtracking at every dead end — finding a path by trying options.
Beat 2 · Abstract
The same, as a tree
Strip the walls away: each choice is a branch. A root expands node by node until the goal node is reached — Logic Theorist proving by search.
Beat 3 · Interactive
Expand it yourself
Each Step expands one node. Watch the frontier multiply — the search space explodes faster than it shrinks.
Frontier grows ×3 per layer — this is the combinatorial explosion ahead.
Where this came from
1956 · 1957
Logic Theorist & GPS
Newell & Simon built programs that proved theorems and solved problems by means-ends search — the first working AI.
1976
Physical Symbol System
Their hypothesis: a system manipulating symbols has the necessary and sufficient means for general intelligence.
1970
SHRDLU · blocks world
Winograd's program understood English commands to stack blocks — fluent reasoning, but only inside a tiny toy world.