Commit 4d8191

2026-04-30 07:56:26 lisa: Data Flow Diagram: add Mark O'Meara DFD videos as Watch first Pairs the same author's 1.5-min revision clip with the 8-min purpose/conventions overview — students new to DFDs work through the longer one first; revision uses the short clip.

sd/C02/Data Flow Diagram.md ..
@@ 11,6 11,18 @@
	---
+	## Watch first (≈10 min total)
+
+	{{Video|src=https://www.youtube.com/watch?v=DXjr63VFiik}}
+
+	*Mark O'Meara (Geelong High School) — 1½-min VCE-targeted revision. Watch for: numbered processes, data stores as parallel lines, and the rule that every flow goes *through* a process.*
+
+	{{Video|src=https://www.youtube.com/watch?v=IDJeqOdIbeI}}
+
+	*Mr O'Meara — 8-min purpose and conventions of a DFD (Yourdon-DeMarco notation). The longer companion to the revision clip — work through this one first if DFDs are new.*
+
+	---
+
	## Why a DFD / what it shows
	Think of the relationship between your context diagram and your Level-1 DFD as the difference between a **satellite view** and a **floor plan**.