Row

Row has no village-craft family origin — concrete objects don't have biographies. Loop, the mentor, introduces Row by demonstration, not story.

Loop sets Row on the workbench and fills it: box 0 gets `"apple"`, box 1 gets `"bread"`, box 2 gets `"milk"`. "This is Row," Loop says. "A list. Stash held one value. Row holds many, in order, each with a position number."

Loop points to box 2. "Position numbers start at 0, so this third box is number 2. Reach in by its number, and you get exactly that value — `milk`. No searching the whole rack. Just ask for the position."

The kid watches Loop pull `bread` straight from box 1. No magic. Just a numbered rack and a position.

Loop demonstrates Row's moves with Bit, the little robot the learner programs.

"Bit needs a shopping list," Loop says. "So we give Bit a Row." Loop loads the list and shows the scaffolds, one at a time: - Reach by position: `list[0]` gets the first value (counting starts at 0). - Add to the end: a new box appears at the next number. - Change a box: swap what's inside without moving the box. - Length: count the boxes to know how many there are. - Walk the row: hand the boxes to a loop, one by one, in order.

"A list doesn't decide anything," Loop says. "It doesn't think. It just holds many values in order and lets you reach any of them by number. That's all a list is."

Loop hands Row to Trek, the loop, so the kid can watch a list and a loop work together — the heart of most real programs.

"Bit, walk the list," Loop says. Trek takes box 0, then 1, then 2, handing each value to Bit. Bit reads `apple`, then `bread`, then `milk`, checking each off. When the boxes run out, the walk ends on its own.

The kid programs Bit to add `eggs` to the end, then walk the whole list again. Bit reads all four, finishes the last one, and stops. Every item handled, in order, none missed.

Reflection: have you ever felt that satisfying feeling of working through a list until everything was done?