In Chapter 6 of Part I, we said that you shouldn’t improvise symbols while you are working because you are likely to forget what the new symbol actually represents and therefore make a serious mistake. However, sometimes you may find yourself in a situation where the speaker is repeatedly talking about a concept that it is very long and slow to write down in words and for which you can think of a quick symbol. If this happens, the safest bet is to prepare for this eventuality in advance by folding over the last page of your note-pad as shown here.