abut
adjacent
analogy
axis
balance
balance concept
beam
black
boulder
clog
cobble
compare
comparison
concept
concept design
conceptual
contiguous
counterbalance
dark
design ideas
differ
equilibrium
equivalence
evenness
flat
gravity
harmony
heaviness
idea
joint
light
nature
notion
object
parallel
parity
pebble
rock
scale
shadow
simile
similitude
simplicity
space
stability
stone
symbol
symmetric
thought
weight