Discuss Shakespeare's presentation of the witches in Macbeth. How dramatically effective is the presentation?

"Fair is foul and foul is fair". Sound familiar to you? This is a catch phrase used by witches in 'Macbeth' and is certainly not forgotten about today. Years ago, witches were seen as a threat to a town or village, a menace and sometimes thought of as 'devils'. Yet, in 'Macbeth', the witches are given a sense of wisdom and knowledge, and are looked to for help by others. Some might even have called …

…is thin, the witches are concocting a spell, using incantations, hand movements and gestures one wouldn't use. Does this atmosphere sound sincere that there's witchcraft going on? Does it not seem that Shakespeare's witches sound convincing because of their faces and personalities and does the atmosphere not make you shiver? I know it makes me shiver, and I agree that Shakespeare has presented the witches dramatic effects so well, I truthfully find the atmosphere convincing.