patterns

type PatternCodes struct {
	// Basic blocks
	FullBlock  rune // F
	TopHalf    rune // T
	BottomHalf rune // B
	LeftHalf   rune // L
	RightHalf  rune // R

	// Shading blocks
	LightShade  rune // .
	MediumShade rune // :
	DarkShade   rune // #

	// Quadrants (1-4)
	Quad1 rune // 1
	Quad2 rune // 2
	Quad3 rune // 3
	Quad4 rune // 4

	// Three-quadrant composites (5-8)
	Quad5 rune // 5
	Quad6 rune // 6
	Quad7 rune // 7
	Quad8 rune // 8

	// Diagonals
	DiagonalBackward rune // \
	DiagonalForward  rune // /

	// Special
	Space rune // _
}