Flippers, Rotators and Tetradics.
So what is the difference between a CS-Flipper, CS-Rotator, and a CS-Tetradic?

CS-Flippers, the simple definition of a CS-Flipper is that you can still read it when you flip it upside down.
M 01698600 M = W 00986910 W.

CS-Rotator it reads the same from left to right, upside down or right side up M 08611980 M = W 08611980 W.

CS-Tetradic reads the same left to right and right to left, right side up or upside down, and if you look at the numbers through the bill from the back, it reads the same as the front. Tetradic numbers are also palindromic.
Front up = M 08111180 M,
Front Down = W 08111180 W,
Through the back M 08111180 M.

Note: one of the keys with CS-Flippers, CS-Rotators, and CS-Tetradics is that they cannot contain 2s, 3s, 4s, 5s, or 7s, as these numbers cannot be read upside down, and in the case of CS-Tetradics, they can only contain 0s, 1s and 8s.

CS-Flippers.
CS-Flippers contain only the numbers 0, 1, 6, 8, and 9, and can be read right side up M 01968100 M and upside down W 00189610 W.

CS-Unary Flipper.
A CS-Unary Flipper M 66666666 M is when all the numbers are the same and they contain all 1s, 6s, 8s, or 9s. A CS-Unary Flipper is also an CS-8OAK. Being both adds a significant premium to the Note.

CS-True Binary Flipper.
A CS-True Binary Flipper contains only 1s and 0s, M 01110001. It is a special case of the CS-Binary Flipper.

CS-Binary Flipper.
A CS-Binary Flipper consists of two distinct numbers from the set of 0, 1, 6, 8, and 9, M 18811181 M.

CS-Trinary Flipper.
A CS-Trinary Flipper consists of three distinct numbers from the set of 0, 1, 6, 8, and 9, M 01810081 M.

CS-Quad Flipper.
A CS-Quad Flipper consists of four distinct numbers from the set of 0, 1, 6, 8, and 9, M 01899901 M.

CS-Quinary Flipper.
A CS-Quinary Flipper consists of all five flipper numbers (0, 1, 6, 8, and 9), and the numbers can still be read upside down M 01698900 M.

CS-Rotators.
With CS-Rotators, when you flip the bill upside down, it must read the same from right to left as when it was right side up. For example, right side up M 01669910 M and upside down W 01669910 W.

CS-Unary Rotator.
A CS-Unary Rotator is also a CS-Solid (CS-8OAK). Being both adds a premium to the Note. The only numbers that it can contain are 1 and 8, M 11111111 M and M 88888888 M.

CS-True Binary Rotator.
A CS-True Binary Rotator only has two numbers in it and those numbers can only be 1s and 0s,
M 01000010 M. This is also a CS-Tetradic.

CS-Binary Rotator.
A CS-Binary Rotator has two numbers in it, and these numbers can be anything but 1’s and 0’s together.
M 06669990 M.

CS-Trinary Rotator.
A CS-Trinary Rotator has three numbers in it, M 06669990 M.

CS-Quad Rotator.
A CS-Quad Rotator has four numbers in it, M 01669910 M.

CS-Quinary Rotator.
A CS-Quinary Rotator has five numbers in it, M 68811889 M.

CS-Tetradic.
A CS-Tetradic reads the same left to right and right to left, and when turned upside down or flipped, it reads the same as right side up, and, if you look at the numbers through the back of the Note, it reads the same as the front, whether right side up or upside down, M 08111180 M. It can only contain 0s, 1s and 8s. The digits in each position 1, 2, 3, and 4 need to match the digits in position 8, 7, 6, and 5, respectively. These are also CS-Palindromes and CS-Full Radars.
Front right side up = M 08111180 M,
Front upside down = W 08111180 W,
Through the back right side up = M 08111180 M,
Through the back upside down = W 08111180 W.

Note: This page contains excerpts and basic information from the book "The Green Guide to Fancy Serial Numbers". Please consider adding a copy to your library, thank you.