🎮 Which Element Is at This Index?

📖 About this game

A game on the lesson of list indexing in programming. Its rule: indexing the elements of a list starts at zero rather than one, and a negative index counts back from the end of the list, so minus one is the last element. Why the buttons are the elements of the list themselves rather than numbers: indexing is an operation that yields an element and not a number, and a learner who touches the element has run the line in his head. Half the rounds use a positive index and half a negative one: a learner who knows only the positive has learned half the lesson, and the negative is where most beginners fall. The first distractor is the element that would sit at that index if counting began at one, which is the expected mistake of this very chapter. The answer is computed from the list and the index at build time rather than typed by hand, and the reveal draws both index ladders, positive and negative, above the elements together, so the learner sees the two on one list. Twelve rounds. No sign-up.

🕹️ How to play

1. Read the list and the print line under it.
2. Remember that counting starts at zero, and that a negative index counts from the end.
3. Tap the element this line prints.
4. Every line you get first try counts for you.