Angie Jimenez is one of the few collectors fortunate enough to own the rare Yost No. 20.  This machine, covered in some detail elsewhere on my site, is unusual in that it is a grasshopper type-action frontstrike, which uses no ribbon.  It is direct-inked, with the type slugs resting on an ink pad.  Many people will never see a Yost upstrike, much less a Yost No. 20; with Angie's detailed shots, all of us can now understand a little better how these machines actually work.
Our first shot actually shows Angie's workshop in operation.  He has an Underwood No. 5 on the table, along with the subject at hand here; the Yost No. 20.
Closer to the Yost now, we can see some identifying details not only of the Yost "visible" machines, but of the No. 20 Yost in particular.

Immediately obvious is the fact that not only are there no ribbon spools visible, but no ribbon.  There is only one object visible at the print point, which is the type alignment guide (found on all Yost machines, whether upstrike or frontstrike.)  No ribbon vibrator, obviously.

Looking at the side of the machine, we see through the side opening a vertical bar.  This is not present on the Yost No. 15, because the No. 15 employed carriage shift.  The No. 20 was a further refinement of the design to incorporate basket shift, and this visual change is in concert with the modifications.
Right up close, we can see the type guide in front of the printing point.  This ensures proper alignment of the type bars and type slugs as they reach the platen. 

Note also the horizontal bar and mountings which are behind the type bars; this isn't present on the No. 15.  You can almost see right through the 15 at this position.

The type slugs are mounted to the type bars by posts.  The cylinders on the type bars are visible here.  Note the different alignment, or angle, of each and every type slug relative to its type bar.  Note also the ink pad holder and ink pad, on which the type slugs rest and by which they are inked for impression.
Here is a wonderful picture.  Angie has operated a series of keys to show various positions that the type bars take on the way to printing.

Note first the ink pad exposed by the raising of the left-most type bars. 

Looking closely, we can see that the type bars have more than one connection point; they actually are each linkages, with what you might call a "main" and a "correcting" motion.  This is necessary to provide the proper travel; a scissors-like linkage is used.  You can see the screw head near the left of the picture, which is on the end of the highest intermediate segment.  This is the drive portion of the type bar action.  Note how the type slugs pull away from the ink pad, and then move up and then back in toward the print point.
Many thanks to Angie for these wonderfully clear and close-up detail shots of the Yost No. 20 "in action," which allow all of us to feel familiar with this rare machine.