<P> Donald Byrd has collected dozens of variants inspired by mathematical concepts and written by himself and others . (A subset of his collection has been published .) Byrd argues that the collection has pedagogic as well as amusement value . Among his variants are: </P> <Ul> <Li> "Infinity bottles of beer on the wall". If one bottle is taken down, there are still infinite bottles of beer on the wall (thus creating an unending sequence much like "The Song That Never Ends"). <Ul> <Li> "Aleph - null bottles of beer on the wall". Aleph - null is the size of the set of all natural numbers, and is the smallest infinity and the only countable one; therefore, even if an infinite aleph - null of bottles fall, the same amount remains . </Li> <Li> "Aleph - one / two / three / etc. bottles of beer on the wall". Aleph - one, two, three, etc. are uncountable infinite sets, which are larger than countable ones; therefore, if only a countable infinity of bottles fall, an uncountable number remains . </Li> </Ul> </Li> </Ul> <Li> "Infinity bottles of beer on the wall". If one bottle is taken down, there are still infinite bottles of beer on the wall (thus creating an unending sequence much like "The Song That Never Ends"). <Ul> <Li> "Aleph - null bottles of beer on the wall". Aleph - null is the size of the set of all natural numbers, and is the smallest infinity and the only countable one; therefore, even if an infinite aleph - null of bottles fall, the same amount remains . </Li> <Li> "Aleph - one / two / three / etc. bottles of beer on the wall". Aleph - one, two, three, etc. are uncountable infinite sets, which are larger than countable ones; therefore, if only a countable infinity of bottles fall, an uncountable number remains . </Li> </Ul> </Li> <Ul> <Li> "Aleph - null bottles of beer on the wall". Aleph - null is the size of the set of all natural numbers, and is the smallest infinity and the only countable one; therefore, even if an infinite aleph - null of bottles fall, the same amount remains . </Li> <Li> "Aleph - one / two / three / etc. bottles of beer on the wall". Aleph - one, two, three, etc. are uncountable infinite sets, which are larger than countable ones; therefore, if only a countable infinity of bottles fall, an uncountable number remains . </Li> </Ul>

Who sings 99 bottles of beer on the wall