a = strsplit(fileread("unixdict.txt"), "\n");
a = intersect(a, cellfun(@fliplr, a, "UniformOutput", false));
a = a(arrayfun(@(i) ismember(fliplr(a{i}), a(i+1:length(a))), 1:length(a)));
length(a)
arrayfun(@(i) printf("%s %s\n", a{i}, fliplr(a{i})), 1:5)