abstract
action
age
appreciate
background
black
cherish
clock
concept
conceptual
countdown
deadline
death
design
disappear
disappearing
dissolving
expire
flow
forward
future
glass
grey
hour
hourglass
lack
late
life
lifetime
metaphor
object
particles
pass
passing
past
running
sand
sandglass
space
speed
spent
table
ticking
time
timer
treasure
urgency
value
vanishing
waste