slog_b(b^z) = slog_b(z) + 1
slog_b(1) = 0

2↑n -> m
2↑m -> n
1.000…∞…1 = slog_2(n)/slog_2(m) = 0.999… = 1

sslog_b(t) = sslog_b(slog_b(t)) + 1
sslog_b(1) = 0

2↑↑n -> m
2↑↑m -> n
1.000…∞…1 = sslog_2(n)/sslog_2(m) = 0.999… = 1