Tick Tock Fugue

Is a two-storey tent
Is a double-D
Is an almost-O
Is a half-B
Is a broken rake
Is a broken E
Is a C gone wrong
Is one minus one
Is just… someone
Is a in the ceiling
Is an elbow, leaning against…
Is an unfinished triangle
Is a V, around 11
Is a tipped-over Z
Is respect for a Z-E-R-O
Is a leaking D
Is an O with its tail showing
Is a leaky P
Is a snake on edge
Is an extremely mixed-up L
Proves that what goes down must come up
Is where parallel lines meet
Is U times two
You know X, the big unknown
Is a fork in the road
Is just two Vs, sleeping together