What is the stress pattern of Macbeth's soliloquy in Act II, scene i?
There are a few lines that are not regular, strictly speaking, but the soliloquy itself is, for the most part, comprised of speech in blank verse: unrhymed iambic pentameter. This means that each line has five feet, each foot consisting of two syllables: one unstressed (or unaccented) syllable followed by one stressed (or accented) syllable. I will try to show the stresses by capitalizing stressed syllables in the words of the quotation below. The end of each foot is marked off by a slash.
I HAVE / thee NOT / and YET / I SEE / thee STILL. /
Art THOU / not, FAtal / VIsion / SENsi / ble (EM syllable)
To FEE / ling AS / to SIGHT? / Or ART / thou BUT /
A DAG / ger OF / the MIND, / a FALSE / CreA / tion (EM syllable)
ProCEE / ding FROM / the HEAT / OpPRESS / ed BRAIN? /
I've used the phrase "EM syllable" to indicate that two lines end with an extrametrical syllable: an additional unstressed (or unaccented) syllable at the very end of the line. It does seem to make sense, however, that this soliloquy would have so many lines that are irregular (like the lines with the extrametrical syllables) because Macbeth's state of mind is disturbed. He is actually hallucinating the murder weapon here, and so his speech seems to be a bit confused, just as his thoughts are.