Errant, Street Artist + Reality Spasm + Teach by Example

Prerequisites

You control at least two mana producing permanents, one of which can tap to produce at least {U}.

Steps

1. Cast Teach by Example by paying {U/R}{U/R}, copying the next instant or sorcery spell you cast.
2. Cast Reality Spasm by paying at least {3}{U}{U}, targeting at least three permanents and choosing the untap mode.
3. Teach by Example triggers, copying Reality Spasm, targeting at least three permanents.
4. Holding priority, activate at least two mana-producing permanents you control by tapping them, adding at least {1}{U}.
5. Activate Errant by paying {1}{U} and tapping it, copying the Reality Spasm copy, targeting Errant and at least two mana-producing permanents you control.
6. Resolve the copy of Reality Spasm from step 3, untapping Errant and at least two mana-producing permanents you control.
7. Repeat from step 4.