I believe the general consensus is that the double dot notation might not have been the best idea. FWIW it's mostly used for inequalities like `(a . <= . b)` w

I believe the general consensus is that the double dot notation might not have been the best idea. FWIW it's mostly used for inequalities like `(a . <= . b)` which some people find easier to read than `(<= a b)`. But `<=` allows more arguments as in `(<= a b c d)` and here the double dot notation can't be used.