The real numbers can be represented by a line going from left to right, with zero in the middle, negative numbers like −1, −2, etc. on the left, and positive numbers, 1, 2, etc. on the right. Then imaginary numbers are represented by a line going up and down the page, with i, 2i, etc. above the middle, and −i, −2i, etc. below. Thus imaginary numbers are in a sense numbers at right angles to ordinary real numbers.
