The nail in the coffin of Lear’s madness is his recreation of his kingly crown in the weeds and plants available to him out on the heath, where he wanders in his banishment. In Act 4, Scene 4, Cordelia offers the audience a useful description of this replacement adornment, calling upon both visual and auditory imagery:
Alack, 'tis he. Why he was met even now
As mad as the vexed sea, singing aloud,
Crowned with rank fumier and furrow-weeds,
With burdocks, hemlock, nettles, cuckoo-flowers,
Darnel, and all the idle weeds that grow
in our sustaining corn.—A century send forth.
Search every acre in the high-grown field,
And bring him to our eye.
What can man's wisdom
In the restoring his bereavèd sense?
He that helps him take all my outward worth.
Cordelia’s description relies on sight and sound imagery woven together to cement the ridiculous sight of the new crown in the audience’s mind. The imaginary sounds of Lear’s singing underscore his madness with auditory imagery, presenting the inane songs he sings as the crashing waves of a stormy sea. Then, Cordelia’s speech appeals to sight as she lists out the constituent plants wreathing his head. This list draws on the extensive tradition of flower and plant imagery in drama and literature, invoked for their pervasive visual language of color and form.
Few playwrights craft tragedies as affecting and emotional as Shakespeare, and he employed this skill to its fullest extent in the haunting closing sequences of King Lear. In Act 5, Scene 3, as Lear himself confronts the body of his daughter Cordelia, Shakespeare treats the audience to a particularly devastating speech that makes use of auditory imagery:
Howl, howl, howl! O, you are men of stones!
Had I your tongues and eyes, I’d use them so
That heaven’s vault should crack. She’s gone forever.
These lines open with the onomatopoeic “howl” of wolves to convey the sound of Lear’s anguish. In keeping with a major theme of the play (the conflation of human and animal behavior), Shakespeare relies on the sound of wild wolves rather than anything more human; Lear’s despair, it would seem, extends beyond the reach of what a human being can express. The use of “howl” also calls to Gloucester’s impassioned speech from Act 3, Scene 7, in which he admonishes Regan for her cruelty to her father by implying that she would rather admit a pack of wolves into her castle than King Lear.
A few lines later, the auditory imagery of the scene shifts once more as Shakespeare evokes the sky-splitting spectacle of thunder and lightning, which “crack” down from the sky and thus contribute to the feeling of torment at play in this section, ultimately preparing the audience for the emotional weight of the very next phrase: "She's gone forever."