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Learn How Slots Work with a Do-It- Yourself Machine

20 September 1999

Learn How Slots Work with a Do-It-Yourself Machine

Most solid citizens are in the dark about how the slots work. I'll help you unravel the mystery, pointing you down the path of discovery by telling you how to make a do-it-yourself machine. And you won't need computer chips, frambibulators, complicated instruction books, or even a screwdriver. Just four sheets of paper, a pen or pencil, four hats, and a modicum of imagination.

Tear the first sheet of paper into 1-inch squares. Write each of the numbers zero through nine on 10 of the squares and drop them into the first hat. Repeat this for two more hats.

Write "Displays" at the top of the second sheet, and the three-digit numbers 000, 001, 002, and so forth down the left edge; stop at 040. Beside 000, draw three stars. Beside each of 001 to 004, draw three circles. Beside 005 to 010, draw -- in order -- **o, *o*, o**, oo*, o*o, *oo. Beside 011 to 020, draw one star. Beside 021 to 030, draw one circle. Leave everything else blank.

Write "Payoffs" across the top of the third sheet and 000 to 040 down the left edge. Beside 000 write "400-800-1500." Beside 001 to 004, write "100-200-300." Beside 005 to 010, write "10-20-30." Beside 011 to 030 write "1-2-3."

Write "Scorecard" at the top of the fourth sheet. Draw a line down the middle of the page. Label the left-hand column "Bets" and the right-hand side "Returns."

Now for the action. Jot the number of coins you play for the round under "Bets." Take a square from each hat. Arrange the picks, as drawn, into a number from 000 to 999. Under "Displays," see what symbols appear on the payline. Under "Payoffs," see what you get back and mark it under "Returns." Values above 030 are three blanks and zero return. Anything else wins. For example, if you bet three and draw 007, o** is on the payline and the return is 30. After each round, replace the squares and go again. When you quit, total the columns on your scorecard; net win or loss is the sum of "Bets" minus "Returns." What about the computers, random number generators, and whatnot you heard are inside the store-bought slots? Machines aren't as good as humans at picking slips out of hats, so former defense contractor rocket scientists had to figure out the second-best way to achieve the same thing.

Here's how to figure theoretical payback percentage. Add up all the 1-coin payoffs; for this machine, it's 880. Divide by 1,000 -- the number of different possible results from 000 through 999. You get 0.88. So, with one coin at a time, this machine has 88 percent payback. Repeat with the 2- and 3-coin payoffs, but divide by 2 and 3, as appropriate, as well as 1,000. You get 88 percent for two coins and 98 percent for three coins.

Knowing there are 1,000 possible results, you can find the chances of various outcomes. One number was the jackpot, so its chance is one out of 1,000. Four numbers paid 100-200-300, so the chance of this return is four out of 1,000. In all, 30 numbers get something back, so the overall hit rate is 30 out of 1,000.

Try stuff on your own. For example, change the "Payoffs" and see how this affects payback percentage. Alternately, pick any 31 numbers smaller than 999 and substitute them for the 000 to 030 on the Displays and Payoffs sheets. Go to multiple paylines by adding extra sets of symbols beside each entry on the "Displays" sheet, leaving the "Payoffs" intact. Look for streaks and patterns, and decide whether they happened by chance or design. And, let your kids take a turn; if they win, ask yourself whether results would have been the same had you played that round.

Try a fourth hat with 10 squares. This gives 10,000 numbers, 0000 to 9999, so the chance of any value is one out of 10,000. To figure payback percentage, divide by 10,000 rather than 1,000. Instead, add numbers 10 through 19 to one, two, or all the original hats; this gives 2,000, 4,000, and 8,000 picks, respectively. Among other things, such variations allow higher jackpots with less chance of being hit. The options are endless, considering that all slots are really the same under their sheet metal. The Sumner A Ingmark rejoiced the pluralism like this:

Choices in a wide variety
Satisfy diverse society.
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Best of Alan Krigman
Alan Krigman

Alan Krigman was a weekly syndicated newspaper gaming columnist and Editor & Publisher of Winning Ways, a monthly newsletter for casino aficionados. His columns focused on gambling probability and statistics. He passed away in October, 2013.
Alan Krigman
Alan Krigman was a weekly syndicated newspaper gaming columnist and Editor & Publisher of Winning Ways, a monthly newsletter for casino aficionados. His columns focused on gambling probability and statistics. He passed away in October, 2013.