This short avant garde film is perhaps Maya Deren’s immortal legacy.  Its historical importance for formal techniques is well established.  I would add, it surpasses most contemporary films, in truly evoking the logic of a dream:

Key – Knife – Man, Knife – Mirror – Self.  A cryptic puzzle, in dream symbols, mirrored selves, circular time, expressed with the abruptness and instability of nightmare.  Perhaps it is about a dream warning a woman about a man…

https://en.wikipedia.org/wiki/Meshes_of_the_Afternoon