# a tit for tat, but a bit more friendly at the beginning
# to avoid hacking on forever on evil-tit-for-tat,
# but be very stringent when the other one defects too often
sub moritz-ctft(:@theirs, :$total,  |$) {
    return True if @theirs < 3;
    return False if @theirs.grep(*.not).elems > ($total / 10);

    @theirs[*-1];
};
%strategies<moritz-ctft> = &moritz-ctft;

# the evil clone...
sub moritz-ectft(:@theirs, :$total,  |$) {
    return True if @theirs < 3;
    return False if @theirs.grep(*.not).elems > ($total / 10);
    # did you believe in happy ends?
    return False if @theirs + 1 == $total;

    @theirs[*-1];
};
%strategies<moritz-ectft> = &moritz-ectft;