Holding priority, activate Rootha by paying ({2} magic symbol) and returning it from the battlefield to your hand, copying Desperate Ritual.
Resolve the copy of Desperate Ritual, adding ({R} magic symbol) ({R} magic symbol) ({R} magic symbol) .
Activate Sneak Attack by paying ({R} magic symbol) , putting Rootha from your hand onto the battlefield.
Repeat from step 2.
If you have another Arcane card in hand, you may either cast that card and splice Desperate Ritual onto it, or splice it onto Desperate Ritual to get infinite copies of the effect(s).