is. this is where your reflections on your seat, tank and lamp will fall. think of the ‘bone’ as the 3d brother to the more 2d foundation line. they work together as a team. here the center of the lamp is right on the bone line: a great decision that ties the whole upper together.
if you get anything right it should be this. it immediately makes the bike look like it really belongs together and is not just a jumble of parts. next time you see a bike (or indeed a car) you like, take some time to see if it has this central ‘bone’ and where it sits. this 