CL-MAZE is a package for generating mazes and rendering them, either to text or as svg images: 
CL-USER> (asdf:load-system "cl-maze")
T
CL-USER> (in-package :cl-maze)
#<Package "CL-MAZE">
CL-MAZE> (render-grid-text (north-east-maze 10 10)) ; NORTH-EAST-MAZE is one particular generator
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+ + + +---+---+ +---+---+ + +
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+ +---+ + +---+ +---+ + + +
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+---+---+ +---+ + + +---+ + +
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+---+ +---+ +---+---+ +---+ + +
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+---+---+ +---+ +---+---+ + + +
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+---+ +---+---+---+---+ + +---+ +
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+---+---+ +---+ +---+---+---+---+ +
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+ + + + + +---+---+ + + +
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+---+ +---+ +---+ + + +---+ +
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+---+---+---+---+---+---+---+---+---+---+
NIL