Three parity pairs show the toy selection rule as checked bits.
Three parity pairs show the toy selection rule as checked bits. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
ground to middle checks the parity pair
The lower parity is even and the upper parity is odd. Different parities give allowed bit 1; matching parities give allowed bit 0. This row's computed bit is 1.
even→odd,allowed=1
middle to upper checks the parity pair
The lower parity is odd and the upper parity is even. Different parities give allowed bit 1; matching parities give allowed bit 0. This row's computed bit is 1.
odd→even,allowed=1
ground to upper checks the parity pair
The lower parity is even and the upper parity is even. Different parities give allowed bit 1; matching parities give allowed bit 0. This row's computed bit is 0.