<Tr> <Th_colspan="2"> Elton John singles chronology </Th> </Tr> <Tr> <Td_colspan="2"> <Table> <Tr> <Td> "The Bitch Is Back" (1974) </Td> <Td> "Lucy in the Sky with Diamonds" (1974) </Td> <Td> "Philadelphia Freedom" (1975) </Td> </Tr> </Table> </Td> </Tr> <Table> <Tr> <Td> "The Bitch Is Back" (1974) </Td> <Td> "Lucy in the Sky with Diamonds" (1974) </Td> <Td> "Philadelphia Freedom" (1975) </Td> </Tr> </Table> <Tr> <Td> "The Bitch Is Back" (1974) </Td> <Td> "Lucy in the Sky with Diamonds" (1974) </Td> <Td> "Philadelphia Freedom" (1975) </Td> </Tr>

What is the song lucy in the sky about