Proofs from the Headshot session with Collette
col-proofs-001col-proofs-002col-proofs-003col-proofs-004col-proofs-005col-proofs-006col-proofs-007col-proofs-008col-proofs-009col-proofs-010col-proofs-011col-proofs-012col-proofs-013col-proofs-014col-proofs-015col-proofs-016col-proofs-017col-proofs-018col-proofs-019col-proofs-020