Tough, open-ended puzzle this month! Many came close, but we received 7 submissions with chains of length 77, which is also the longest we could find. Congratulations to Alexander Chappell, one of the 7, and this month’s randomly chosen winner of a Jane Street t-shirt! His submission was: 69 23 46 92 4 76 38 19 95 5 85 17 68 34 2 62 31 93 3 87 29 58 1 49 98 14 56 28 84 42 21 63 9 81 27 54 18 72 36 12 6 66 33 99 11 22 44 88 8 24 48 96 32 64 16 80 40 20 60 30 90 45 15 75 25 100 50 10 70 35 7 91 13 39 78 26 52