Bush's memex (#3, As We May Think) saved the trail you took through documents. Petricek's Histogram (#15) saves a program as the list of interactions that built it, then shows that list as code or as a spreadsheet. Same bet from 1945 and today: the path is the artifact, not the pile it passed through.

Try it: next time you reach an answer in a spreadsheet, write down every cell you touched in order, then hand that list, not the sheet, to someone else. See whether they reach the same number, and where they stop to ask why.

Dynamicland (#8, Bret Victor and team) puts programs on paper in a shared room. Chalktalk (#26, Perlin, He and Rosenberg) puts them on a drawn glyph that you click to run. Both make code something you point at, not something you open.

The difference worth testing is who can reach in. In a room, anyone standing there can move a page. In Chalktalk, whoever holds the pen decides.

Try it: sketch one small simulation on paper, a ball and a wall, and hand the paper to someone else. Note where they reach first, and what they change without asking.

Chalktalk (#26) turns a drawn glyph into a live sketch you can link to other sketches: its binary tree takes a swipe to undo and a drawn curve to trigger a traversal. Crosscut (#23) starts from the same instinct, a stylus on a page that keeps the looseness of paper and gains the behavior of a model.

The Chalktalk paper is candid about what is missing: no formal evaluation, a stack and a tree that cannot yet call each other, a link type system still in research. That candor is the useful part.

Try it: draw a stack on paper and name two operations, push and pop. Then ask what a second drawing, a tree, would need to send the first for the two to explain a call stack together.