[tromp]

According to English letter frequencies [1] that gives a right probability of 3.0129+6.6544+7.1635+3.1671+0.1962+7.5809+5.7351+6.9509+3.6308+1.0074+1.2899+0.2902+1.7779+0.2722 = 48.7294 % even though you summed 14 of the 26 letters (a 13-13 split would lower the probability to 45.7165%).

[1] https://www3.nd.edu/~busiforc/handouts/cryptography/letterfr...

[NeoTar]

I wonder if the patterns of letters in English language usage would still yield predictable patterns of left-and-right. Like naively 'the' is more common than 'zzz', so right-left-left may be more common than right-right-right.