Spark & Anvil Privacy
A warm library map room with a large blank map spread on a wooden table, string and pins marking regions, two teenagers redrawing boundaries

🗳️

DistrictForge

The same votes, redrawn, can hand one side twice the seats. See how lines become power — and measure it.

🔮 Open the redistricting console →

Why who draws the lines matters

In a winner-take-all system, a district gives its whole seat to whoever gets the most votes there — so a party’s share of the SEATS can be nothing like its share of the VOTES. That gap is a choice: whoever draws the district lines can pack an opponent’s voters into a few landslide districts (wasting them) or crack them thin across many (so they always just lose). DistrictForge lets you draw the same state two ways with the identical 55% vote and watch the seats swing — then measure the unfairness with the efficiency gap, the metric argued before the Supreme Court. Two synthetic parties, Violet and Orange — non-partisan by construction.

  1. Vote ≠ seats. Winner-take-all means a modest majority, spread evenly, can win everything.
  2. Pack. Concentrate an opponent into a few districts they win huge — wasting their extra votes.
  3. Crack. Spread them thin so they lose everywhere by a little — wasting all of them.
  4. Measure. The efficiency gap = one side’s wasted votes minus the other’s, over all votes.

Everything runs on your device with exact arithmetic — no library, no network.

The pieces of a map

  • The district — winner-take-all: whoever gets the most votes takes the whole seat, so surplus and losing votes elect no one.
  • Packing — drawing an opponent into a few districts they win in a landslide, so their extra votes are wasted.
  • Cracking — splitting an opponent across many districts so they fall just short in each, wasting all their votes.
  • The efficiency gap — (one party’s wasted votes − the other’s) ÷ all votes; above about 7% flags a likely gerrymander.

A console for ages 15–18 — no cast art here by design.

What next? Pick a door

Chosen from what this app is about. What you open is remembered on this device only.