Sometimes the solution to a problem is obvious … at least once someone else has pointed it out:
Recently, when writing a check, it occurred to me that requiring the amount to be given separately in both words and number was a simple and ingenious solution to the problem of reducing error. It is possible, if your handwriting is as sloppy as mine, to write a letter or number that can be misread as a different letter or number. If redundancy consisted of writing the amount of the check twice as numbers or twice as words the same error could appear in both versions. It is a great deal less likely to make two errors, one in letters and one in numbers, that happen to produce the same mistaken result. It reduces the risk of fraud as well, for a similar reason.
That is one example of a simple and elegant solution to a problem, so simple that until today it had never occurred to me to wonder why checks were written that way. Another example of the same pattern is a nurse or pharmacist checking both your name and date of birth to confirm your identity.1
That started me thinking about other examples:
The design of rubber spatulas, one bottom corner a right angle, the other a quarter circle. One of the uses of the device is to scrape up the contents of containers, jars and bowls and such. Some containers have curved bottoms, some flat bottoms at a right angle to the wall. The standard design fits both.
Manhole covers are round because it is the one simple shape such that there is no way of turning it that lets it fall through the hole it fits over.
Consider an analog meter with a needle and a scale behind it. If you read it at a slight angle you get the reading a little high or low. Add a section of mirror behind the needle and line up the image behind the needle. Problem solved.
If you try to turn a small screw with a large screwdriver it doesn’t fit into the slot. Turning a large screw with a small screwdriver isn’t always impossible but if the screw is at all tight you are likely to damage the screwdriver doing it. The solution is the Phillips screwdriver. The tip of a large Phillips screwdriver is identical to a smaller one so can be used on a range of screw sizes.2
Ziplock bags have been around since the sixties. Inventing them was not simple but a new application is: packaging that consists of a sealed plastic bag with a Ziplock below the seal. After you cut open the bag you can use the ziplock to keep the contents from spilling or drying. I do not know how recent an innovation it is but I cannot recall an example from more than a decade ago.
1. This one and some of the others were suggested by posters on the web forum Data Secrets Lox.
2. I am told that the solution is not perfect, doesn’t work for very small screws, which require a smaller size of driver.
