The collaboration may be very limited indeed, when John Green and David Levithan wrote "Will Grayson, Will Grayson" the only plot point they decided on was that two characters would meet at some point in the novel and that their meeting would have a tremendous effect on their lives. After this decision, they separately wrote the first three chapters for their half and then shared them with each other. After sharing, they then "knew immediately it was going to work", as stated by Levithan.