Do you really want to send Professor Pi a message saying you like their work?
The general formula for unsubstituted alkenes is CnH2n
H H \ / C=C / \ H H Ethene C2H4 H H \ | C=C-C-H / | | H H H Propene C3H6 H H H H H \ | | | | C=C-C-C-H H-C-C=C-C-H / | | | | | | | H H H H H H H H 1-Butene C4H8 2-Butene C4H8