Port of the FMZ open-source strategy 'Buy then Sell (ping-pong strategy)' by Zero (fmz.com/strategy/169227). The original rests ONE limit buy at a fixed absolute price (BUYPRICE=7800, BUYAMOUNT=0.1 BTC). Once the fill shows up in the balance, it rests a limit sell for the filled quantity at a fixed absolute price (SELLPRICE=8000). It never stops out and never repeats. Taken literally it is a single trade at 2019 BTC prices: 7800/8000 cannot fill against today's prices, and one trade cannot be backtested. So it counts as a strategy, but it is not viable as written. The only scale-free content in the defaults is the buy/sell geometry: the sell sits 8000/7800 - 1 = +2.564% above the buy, and the buy sits 7800/8000 = 97.5% of the sell level. This port keeps that geometry exactly. It turns the absolute prices into a reference-relative pair: the reference R is the sell-side anchor (the '8000'), and the buy rests at 0.975 x R (the '7800'). To produce a sample, the pair re-arms every UTC day while flat. Adaptations limited to venue, instrument, sizing and fees: (1) venue BINANCE_SPOT. The original is a long-only, unleveraged cash buy-then-sell, which is exactly the spot CASH account. (2) instrument ETHUSDT instead of BTC_USD. BTC is heavily over-represented in the corpus and the mechanism is not BTC-specific; ETH spot has 8+ years of Binance history. (3) sizing is 50% of equity per cycle instead of a fixed 0.1 BTC. (4) one platform-mandated addition that the original lacks: a 30-day safety clock (market exit), so a position cannot be held without limit. The platform's holding-period gate is <=90 days and an unbounded bag-hold cannot pass risk review. This is flagged as a deviation, and a 'no clock' variant can be scored separately. Honest caveat (lesson L167): public-script ports usually die. This one survives the fee regime on paper because its target (+2.56%) is ~13x the spot round trip. The real question is whether the fat left tail from the clock exits eats the high hit rate. Flat state: flat between a sell fill and the next day's re-arm, and on days the buy does not fill. Expected time-in-market is ~45-60%.