THE GENERATION OF CHANGES
| There are six changes on three bells.
They are produced by crossing over alternate pairs as shown alongside:- | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 1 | 2 | 3
| x |
| 2 | 1 | 3
| x |
| 2 | 3 | 1
| x |
| 3 | 2 | 1
| x |
| 3 | 1 | 2
| x |
| 1 | 3 | 2
| x |
| 1 | 2 | 3
| |
| 1 | 2 | 3 | 4
| x | x | x | (i) To cross both pairs of bells, viz 1 & 2 and 3 & 4 | 2 | 1 | 4 | 3
| 1 | 4 | x | (ii) To produce the next row 1 & 4 are crossed whilst 2 & 3 are said to "make a place" in first place and fourth place | 2 | 4 | 1 | 3
| x | x | x | Steps (i) and (ii) are repeated to produce rounds backwards.
| 4 | 2 | 3 | 1
| 1 | 4 | x |
| 4 | 3 | 2 | 1
| x | x | x | To continue these steps will return the bells to rounds. | 3 | 4 | 1 | 2
| 1 | 4 | x |
| 3 | 1 | 4 | 2
| x | x | x |
| 1 | 3 | 2 | 4
| 1 | 4 | x |
| 1 | 2 | 3 | 4
| |
This generates eight different changes (1 2 3 4 occurs at the beginning and end) and the system of doing so is called PLAIN HUNT.
The small crosses between the rows are to show the pairs crossing. The figures on the left, between the rows, indicate that "places were made" in first and fourth places, while the other bells crossed. The crosses in the same column show that all the pairs crossed. Reading this column downwards gives x 14 x 14 x 14 x 14 and is called the PLACE NOTATION by which the changes were generated.
There are 24 permutations of 4 bells (1 times 2 times 3 times 4 = 24). To generate these, at the END of the PLAIN HUNT, places are made at ONE and TWO instead of ONE and FOUR, to produce the row 1 3 4 2 at the Treble's second blow at lead.
The PLAIN HUNT process is then repeated until the Treble again leads, when the PLACES are again MADE in ONE and TWO to produce 1 4 2 3 at the Treble's second blow at lead. A third cycle will produce ROUNDS after a total of 24 changes.
PLAIN BOB on 4 bells is called PLAIN BOB MINIMUS.
PLAIN BOB on 6 bells is called PLAIN BOB MINOR and is generated in the same way. Places are made at ONE and SIX to produce PLAIN HUNT and at ONE and TWO when the Treble leads. PLAIN BOB MINOR returns to ROUNDS after 60 changes.
Since there are 120 possible changes on 5 bells and 720 possible changes on 6 bells, PLAIN BOB can be extended using BOBS. A BOB is made by altering where the "place is made" when the treble leads from second place to fourth place. (BOBS are not needed in MINIMUS).