While they are sleeping someone apparently teaches them that the past tense of lead (pronounced leed) is lead (pronounced led), but the fantastic word that is the past tense is actually led, because if you make the past tense lead, you have been reading the periodic table of elements for element 82 which is Pb, and that tells you right there that lead (pronounced led) is not the past tense of lead (pronounced leed), but the proper past tense spelling is led, thank you very much.