convexity

Lev Vygotsky’s Лев Семёнович Вы́готсого idea of the zone of proximal development looks like a topological vector spacescaling

  • as number of coworkers is increased,
  • as number of supervisors is increased,
  • as skill level is increased.

two 8 yr. old children may be able to complete a task that an average 8 yr. old cannot do. Next, more difficult tasks are presented with very little assistance from an adult.

5

1-3/4” Rose quartz plugs, this pair has one concave and one slightly convex face. Lots and lots of blue iridescence inside this particular piece of stone!

Ribbed Glass Bowl

Roman

1st Century A.D.

This type of vessel represents a Roman manufacturing breakthrough that made high-quality glassware broadly affordable for the first time. The ribs were pressed into a heated glass disk with a tool, and then the disk was heated over a convex form. The resulting bowl shape was slowly cooled and then turned on a lathe to polish the rim and apply incised detail. Finally, the bowl was fire-polished in the furnace. It is in pristine condition.

Source: The Cleveland Museum of Art