diff --git a/bit/debit.go b/bit/debit.go
new file mode 100644
index 0000000..f3ec67c
--- /dev/null
+++ b/bit/debit.go
@@ -0,0 +1,22 @@
+package bit
+
+type Debit uint8
+
+type Debits []Debit
+
+func toDebits(b byte) Debits {
+	var o = make(Debits, 4)
+	for bit, mask := 0, byte(128); bit < 8; bit, mask = bit+2, mask>>2 {
+		o[bit/2] = Debit((b >> mask) & 3)
+	}
+	return o
+}
+
+func NewDebits(bytes []byte) Debits {
+	var l = len(bytes)
+	var o = make(Debits, 0)
+	for i := 0; i < l; i++ {
+		o = append(o, toDebits(bytes[i])...)
+	}
+	return o
+}
diff --git a/bit/mask.go b/bit/mask.go
new file mode 100644
index 0000000..7eb274f
--- /dev/null
+++ b/bit/mask.go
@@ -0,0 +1,261 @@
+package bit
+
+// Because Go doesn't have binary literals ("We've found hex and octal to be sufficient")
+const (
+	B00000000 = iota
+	B00000001
+	B00000010
+	B00000011
+	B00000100
+	B00000101
+	B00000110
+	B00000111
+	B00001000
+	B00001001
+	B00001010
+	B00001011
+	B00001100
+	B00001101
+	B00001110
+	B00001111
+	B00010000
+	B00010001
+	B00010010
+	B00010011
+	B00010100
+	B00010101
+	B00010110
+	B00010111
+	B00011000
+	B00011001
+	B00011010
+	B00011011
+	B00011100
+	B00011101
+	B00011110
+	B00011111
+	B00100000
+	B00100001
+	B00100010
+	B00100011
+	B00100100
+	B00100101
+	B00100110
+	B00100111
+	B00101000
+	B00101001
+	B00101010
+	B00101011
+	B00101100
+	B00101101
+	B00101110
+	B00101111
+	B00110000
+	B00110001
+	B00110010
+	B00110011
+	B00110100
+	B00110101
+	B00110110
+	B00110111
+	B00111000
+	B00111001
+	B00111010
+	B00111011
+	B00111100
+	B00111101
+	B00111110
+	B00111111
+	B01000000
+	B01000001
+	B01000010
+	B01000011
+	B01000100
+	B01000101
+	B01000110
+	B01000111
+	B01001000
+	B01001001
+	B01001010
+	B01001011
+	B01001100
+	B01001101
+	B01001110
+	B01001111
+	B01010000
+	B01010001
+	B01010010
+	B01010011
+	B01010100
+	B01010101
+	B01010110
+	B01010111
+	B01011000
+	B01011001
+	B01011010
+	B01011011
+	B01011100
+	B01011101
+	B01011110
+	B01011111
+	B01100000
+	B01100001
+	B01100010
+	B01100011
+	B01100100
+	B01100101
+	B01100110
+	B01100111
+	B01101000
+	B01101001
+	B01101010
+	B01101011
+	B01101100
+	B01101101
+	B01101110
+	B01101111
+	B01110000
+	B01110001
+	B01110010
+	B01110011
+	B01110100
+	B01110101
+	B01110110
+	B01110111
+	B01111000
+	B01111001
+	B01111010
+	B01111011
+	B01111100
+	B01111101
+	B01111110
+	B01111111
+	B10000000
+	B10000001
+	B10000010
+	B10000011
+	B10000100
+	B10000101
+	B10000110
+	B10000111
+	B10001000
+	B10001001
+	B10001010
+	B10001011
+	B10001100
+	B10001101
+	B10001110
+	B10001111
+	B10010000
+	B10010001
+	B10010010
+	B10010011
+	B10010100
+	B10010101
+	B10010110
+	B10010111
+	B10011000
+	B10011001
+	B10011010
+	B10011011
+	B10011100
+	B10011101
+	B10011110
+	B10011111
+	B10100000
+	B10100001
+	B10100010
+	B10100011
+	B10100100
+	B10100101
+	B10100110
+	B10100111
+	B10101000
+	B10101001
+	B10101010
+	B10101011
+	B10101100
+	B10101101
+	B10101110
+	B10101111
+	B10110000
+	B10110001
+	B10110010
+	B10110011
+	B10110100
+	B10110101
+	B10110110
+	B10110111
+	B10111000
+	B10111001
+	B10111010
+	B10111011
+	B10111100
+	B10111101
+	B10111110
+	B10111111
+	B11000000
+	B11000001
+	B11000010
+	B11000011
+	B11000100
+	B11000101
+	B11000110
+	B11000111
+	B11001000
+	B11001001
+	B11001010
+	B11001011
+	B11001100
+	B11001101
+	B11001110
+	B11001111
+	B11010000
+	B11010001
+	B11010010
+	B11010011
+	B11010100
+	B11010101
+	B11010110
+	B11010111
+	B11011000
+	B11011001
+	B11011010
+	B11011011
+	B11011100
+	B11011101
+	B11011110
+	B11011111
+	B11100000
+	B11100001
+	B11100010
+	B11100011
+	B11100100
+	B11100101
+	B11100110
+	B11100111
+	B11101000
+	B11101001
+	B11101010
+	B11101011
+	B11101100
+	B11101101
+	B11101110
+	B11101111
+	B11110000
+	B11110001
+	B11110010
+	B11110011
+	B11110100
+	B11110101
+	B11110110
+	B11110111
+	B11111000
+	B11111001
+	B11111010
+	B11111011
+	B11111100
+	B11111101
+	B11111110
+	B11111111
+)