Ok, if you have a phrase, or saying, or just a fact you can turn it into a ditloid.
For example - 365 days in a year would be 365 d in a y. They are used in quizzes etc. The fact needs to have a number in it, then you just use the first letter of the word to represent it.
Some more examples - 18 H on a GC is 18 holes on a golf course
23 P of C in the HB is 23 pairs of chromosomes in the human body.. hope this helps
The word 'ditloid' actually comes from the title of the Alexander Solzhenitsyn novel 'One Day In The Life Of Ivan Denisovich'. That can, of course be abbreviated to "I = ditloid'. Hence, all of these incredibly tedious other examples.