The Plumb, when placed at either end of the Level, forms the Square.
To say that the Masters jewel is made of the two immediately lesser jewels, is to say that the Master, to be properly prepared, should have served and worn both lesser jewels.
Every Mason, holding an elected or appointed office, should learn the extensive allegory of the jewel he wears. Every jewel' in the Masonic order will lead it's researcher into the Holy Bible.
At least once during the term of every officer., he should present to the Craft, the allegory of his jewel.
The Masters jewel, The square, is an angle of 90 degrees, or fourth part of a circle.
The Square, when inverted and extended to a semi-round, becomes the Quadrant and the true fourth part of a circle.