Why we pivoted then
Every open item in F2's table is closed; the code-layer and other-language rows stay blocked because they change the known letters or need a codebook. F4 is sixth in the ranking, after F2; the ranking is unchanged.
What happened before
- 0181: 0057 struck every copy of one or two letters as filler and left keys of 24-25 that fit as often as chance. What those keys force outside the known words holds no dictionary word of 6 or more letters on K4. The scrambled copies hold one in 0-32 settings.
- 0182: for a repeating or progressive key, any rule for placing nulls acts only through how many nulls fall between the two known words. Every count from 0 to 29 was tested exactly, and K4 is never above its copies.
- 0183: a 26-letter phrase with repeated letters as the plain strip, so that letters have homophones while the length stays the same. 1,196 phrases from the sculpture's texts and Carter's book fit K4 only at key length 26, where there is a single check.
The change we believe is needed
- F4 next, in its table's order: F4.1 (routes that follow the plates' layout), F4.2 (free trifid cubes above period 15), F4.3 (the physical anomalies as a key), F4.4 (the extra L and the HILL row as a marker), F4.5 (Antipodes' differences).
- F4.1 needs the plate layout. The transcript's 28 lines give K4's place on the lower-left plate: it starts at the 28th character of line 25, after K3's last letters and the "?". The compiled route tester built for F6 tests any list of routes against a repeating key on the sculpture's tables.