Fischer Projections of L-Erythrose

All of the images below are for L-erythrose. This tutorial has all of the 3-D images in staggered confromations. Rotate the images so see how the 3-dimensional model correlates with the Fischer projections. You can use any of the 3-D images to see all nine Fischer projections by first correlating the top chiral center and then rotating the molecule around the vertiacal axis to see the bottom center. The excercise demonstrates how all nine projections are for the same molecule. All are correct. It is a matter of perspective which one is drawn. The convention for sugars is to use the first projection on the left, with the aldehyde or ketone on top and the CH2OH on the bottom. For typical organic molecules there is no convention for which perspective is best.
Red = Oxygen, Grey = Carbon, White = Hydrogen