DNA Supercoiling & Topoisomerase Simulator (2D)

A 2D companion to the 3D DNA supercoiling model: a closed DNA loop drawn flat, obeying the same real topological law Lk = Tw + Wr. A tracking enzyme moving around the loop locally unwinds the duplex, forcing over-winding ahead and under-winding behind — watch the loop itself buckle into tight plectonemic coils as the local twist deficit is genuinely converted into writhe. Click Topo I or Topo II to apply one real discrete catalytic cycle (Δ Lk = ±1 or ±2) and watch the coiling relax immediately. A live check confirms the enzyme's own motion never changes total Lk — only a topoisomerase click does.