A two lead Turkshead or thee lead Turkshead can be expanded to increase bights only. A TH with more than 3 leads cannot be expanded to increase bights only, it must be raised in a manner that will increase leads and bights
The smallest two lead TH is a two lead x three bight knot, also known as an overhand knot. It can be expanded to a 2 lead x 5 bight, 7 bight, etc. Any two lead TH can then be raised to a 4 lead TH. A 2 lead x 3 Bight TH will raise to a 4 Lead x 5 bight, and then a 6 lead x 7 bight. A 2 lead x 5 bight TH will raise to a 4 lead x 9 bight, and then a 6 lead x 13 bight.
A three lead TH can increaase the number of bights only by 'continuing the braid'. Start by pulling some extra line into the knot to give yourself some more room in the knot. Spread the knot apart so there is a large gap between where the standing part enters the knot, and the working end comes out. There will be two leads running the length of this gap. To continue the braid, pass the working end between these leads, and then cross the leads and pass the working end through the gap between the crossed leads. This method will allow you to continue the three strand braid pattern of a 3 lead TH using only the working end of line.
A 3 lead x 4 bight TH will become a 3 lead x 7 bight, and then a 3 lead x 10 bight, etc. A 3 lead x 4 bight TH will expand to a 5 lead x 6 bight, and then a 7 lead x 8 bight. A 3 lead x 7 bight will expand into a 5 lead x 11 bight, and then a 7 lead x 15 bight etc.
A 3 lead x 2 bight TH will become a 3 lead x 5 bight, and then a 3 lead x 8 bight, etc. A 3 lead x 2 bight TH will expand to a 5 lead x 4 bight, and then a 7 lead x 6 bight. A 3 lead x 5 bight will expand into a 5 lead x 9 bight, and then a 7 lead x 13 bight etc.
Using this method you can find your way to many of the possible Turksheads that are generally square, or have more bights than leads.
Pat