Another view of an image of an RER granule from an alveolar type II cell. where an actual SP-A shadow cast molecule (from the internet) was duplicated, mirrored vertically, both copied again, and pasted so that four molecules are stacked. These then were placed next to an opportune profile of an RER granule which clearly showes 4 ribosomes in a period….  As previously mentioned, one ribosome for each of the most dense layers (that is at the widths of the single periods) and two ribosomes within the period, one on either side of the central dense band.  4 ribosomes per period in all….  which pretty much matches the concept of four SP-A molecules end on end as imaged here. Still thinking on this, comments (to my personal email, not on this blog page) are welcome.