From the Mystara Mailing List posted 07 November 1998.
The pentagram is a magical circle necessary for ritual magic. As the name implies the pentagram has five corners. Each symbolising one of the Five Spheres. The top must always point north. This corner represents Matter. going clockwise the following representations of the spheres should be Thought, Entropy, Energy and Time. If the top of the pentagram points south and is invoked with the Sphere of Entropy, then this is a reversed Pentagram. This is a dangerous use of the Pentagram, but it is useful for summoning demons and other infernal creatures.
In a regular pentagram, Matter should always be invoked first, then moving clockwise, ending with Time. After the magic has been worked, the process must be reversed moving counter clockwise. Invoking the Spheres is done by walking with a staff, drawing a circle around the Pentagram. When you reach one of the corners, a candle must be lit and a small ritual is performed with the appropriate wands.
A wand is not necessarily an actual wand. There are five magical tools, one representing each of the Spheres. For matter, a stone, for thought, a mirror is used. For Entropy, a skull, for energy a dagger and for Time a cup. These items need not be enchanted, but they must be decorated, preferably by the caster himself. While performing spells, the caster must be in the centre of the pentagram, leading all the forces from the spheres toward him. He (or she) should be naked or wearing a thin robe as the caster must not be distracted by any material discomforts.
A pentagram can also be used to trap extraplanar beings. When this is done the caster must be outside the circle.