US Sailplane IGC / XCscore / FAI Badge Flight Validator

Parse & validate FEN board snapshots, PGN/SAN movetext (with parity, check/mate counts, threefold); compute Elo rating updates from win/draw/loss results, with Lichess/Chess.com tier bands

Decode leetspeak (1337) to plain text and score how plausibly leet an input is — for password-policy bypass screening, profanity-filter evasion, and log-noise filtering.

A complete in-browser formal-verification stack — no cvc5/Z3 binary needed: an SMT-LIB 2.7 script parser for the QF_BV + Bool core with Tseitin bit-blasting of the FixedSizeBitVectors operators (add/sub/mul/udiv/urem, shifts, comparators, concat/extract/extend, ite), an AIGER reader (ASCII aag and binary aig with delta decoding; outputs as bad properties), a BTOR2 reader with word-level bit-blasting, and a hand-written CDCL SAT engine (two-watched literals, VSIDS-style activities, 1-UIP learning, restarts) underneath. On sequential models it runs bounded model checking with counterexample-witness traces, k-induction with unique-state strengthening, McMillan-style Craig interpolation computed from the refutation and independently re-certified by SAT before being trusted, and an IC3/PDR-lite frame loop with predecessor-cube blocking.

Convert between letters and numbers (A=1, B=2, … Z=26) with configurable separator and case, decode numbers back to letters, and compute the letter sum of any text.