[ because I really hate drawing diagrams ]
Code your diagram here


Remind me about my options?

// no arrow

a -- b

a .. b

// arrows (and in the other direction)

a -> b

a ..> b

// diamonds (or in both directions)

a -<> b

a ..<> b

// colours and messages

a {red} .. b {#ffb700} : o hai arrow!

Image comes out here