MARKING STYLE :
Their doorstops were marked with the Letters " LVL
the "L is made, not at a 90 degree angle, more like 60 degrees
Sometimes there was a " " Symbol in front of the LVL
And, sometimes they added " PAT APPL FOR "   or " PAT PEND "
An example of a doorstop with both is seen in views "M1a" & "M1b"
DOORSTOPS MADE BY LVL :
WOMAN IN RUFFLED DRESS WITH 2 BOWS
ART DECO FLOWERS
OXEN, PIONEERS & WAGON