The following symbols are arranged in a 4x4 grid.
One symbol has to be replaced because it spoils the
logical arrangement. Which symbol is wrong?
Correct answer: N
Explanation:
This one is somewhat tricky. You need to interprete a white slice as zero and a red slice as one. Then sum up the symbols row by row and column by column using binary addition of the slices at the same position. Only the least significant bit is kept, which means the following cases might appear:
0+0+0+0 = 0 -> white
0+0+0+1 = 1 -> red
0+0+1+1 = 10 -> white (1 is the most significant bit and is omitted)
0+1+1+1 = 11 -> red
1+1+1+1 =100 -> white (10 are omitted)
In other words: an even number of red slices (0,2,4) becomes a white slice, an odd number (1,3) becomes red.
After doing so you will up with the result shown in the image below.
If you now compare the results of the rows with the columns (blue arrows) you will find two pairs of identical symbols while the other two pairs are only slightly different. This is due to two wrong neighboring segments in symbol N (they are switched). If you exchange these wrong segments in symbol N you will get four matching pairs.
