Polypentadecathlon

A polypentadecathlon is any period-15 oscillator in which multiple copies of the pentadecathlon interact, generally in a non-trivial way. Many smaller examples of these have been noted to occur naturally in asymmetric soup.

Pentadecathlon pairs

A pentadecathlon pair, or bi-pentadecathlon, involves one pentadecathlon reacting with another to a given extent.

True pentadecathlon pairs

Much like other combination patterns such as standard spaceship flotillae, one pentadecathlon will result in the other pentadecathlon evolving in a different way than if it were not present. There exist at least 32 different possibilities:

Image	Wiki name apgcode	Cells	Commonness	Synth. cost	Other names
					Catagolue	Niemiec
	Pentadecathlon pair 1 xp15_4r4y14r4z4r4y14r4	24	first	6	bi-pentadecathlon 1	Two pentadecathlons #1
	Pentadecathlon pair 2 xp15_sksy1vtvzvnvy1757	24	second	7	skewed bi-pentadecathlon 1	Two pentadecathlons #2
	Pentadecathlon pair 3 xp15_uquy3vtvzfbfy3757	24	no natural occurrences	6	N/A	Two pentadecathlons #4
	Pentadecathlon pair 4 xp15_sksy3vtvzvnvy3757	24	twenty-fifth	6	bi-pentadecathlon with centre domino	Two pentadecathlons #5
	Pentadecathlon pair 5 xp15_0gy34r4z2t2y24r4z2d2	24	seventeenth	6	N/A	Two pentadecathlons #6
	Pentadecathlon pair 6 xp15_4r4y1uquz4r4y1fbf	28	seventeenth	7	bi-pentadecathlon 2	Two pentadecathlons #7
	Pentadecathlon pair 7 xp15_4r4y2sksz4r4y2vnv	28	twelfth	7	N/A	Two pentadecathlons #8
	Pentadecathlon pair 8 xp15_4r4y2eaeeeeaez4r4	28	third	6	N/A	Two pentadecathlons #20
	Pentadecathlon pair 9 xp15_gcgy275777757zgfgz03	28	eighth	6	N/A	Two pentadecathlons #21
	Pentadecathlon pair 10 xp15_3v3y1vtvz9g9y1757zcfc	30	seventeenth	7	N/A	Two pentadecathlons #10
	Pentadecathlon pair 11 xp15_cscy1vtvz434y1757zhuhz111	30	seventeenth	7	N/A	Two pentadecathlons #12
	Pentadecathlon pair 12 xp15_75777757zwss888kwk888ss	30	sixteenth	7	N/A	Two pentadecathlons #13
	Pentadecathlon pair 13 xp15_vtvz757zza9azaiaz06	30	no natural occurrences	6	N/A	Two pentadecathlons #16
	Pentadecathlon pair 14 xp15_2252222522y24ahhhhhha4	30	seventeenth	6	N/A	Two pentadecathlons #17
	Pentadecathlon pair 15 xp15_ijizmgmy475777757z4c4	30	fourth	6	N/A	Two pentadecathlons #22
	Pentadecathlon pair 16 xp15_vtvy2ehhey0ehhez757	30	ninth	6	N/A	Two pentadecathlons #23
	Pentadecathlon pair 17 xp15_0oy14evy2ve4z1u1z161	30	twelfth	6	N/A	N/A
	Pentadecathlon pair 18 xp15_4r4y2s88s0ss0s88sz4r4	31	ninth	6	N/A	Two pentadecathlons #27
	Pentadecathlon pair 19 xp15_9f9zbrbz232y0vtvzy3757	32	sixth	7	N/A	Two pentadecathlons #14
	Pentadecathlon pair 20 xp15_04evy2ve4zss888mwm888ss	32	twenty-seventh	8	N/A	Two pentadecathlons #15
	Pentadecathlon pair 21 xp15_4ahhhhhha4y14evy2ve4	32	no natural occurrences	6	N/A	Two pentadecathlons #18
	Pentadecathlon pair 22 xp15_0gxehhey0ehhez2t2z2d2	32	seventeenth	6	N/A	Two pentadecathlons #24
	Pentadecathlon pair 23 xp15_9f9zbrby275777757z232	32	twenty-fifth	6	N/A	Two pentadecathlons #25
	Pentadecathlon pair 24 xp15_vtvy18sws0kk0sws8z757	32	fifth	6	N/A	Two pentadecathlons #26
	Pentadecathlon pair 25 xp15_vtvy0e0hh0ewe0hh0ez757	32	fifteenth	7	N/A	N/A
	Pentadecathlon pair 26 xp15_3v3z9g9y14evy2ve4zcfc	32	fourteenth	6	N/A	N/A
	Pentadecathlon pair 27 xp15_vtvx44ewe4444ewe44z757	32	twenty-seventh	7	N/A	N/A
	Pentadecathlon pair 28 xp15_474z1v1y3eaeeeeaez9p9z01	32	no natural occurrences	6	N/A	N/A
	Pentadecathlon pair 29 xp15_75777757z4s4zdddz9f9	32	seventeenth	6	N/A	Two pentadecathlons #29
	Pentadecathlon pair 30 xp15_vtvy2e44e0ee0e44ez757	32	sixth	6	N/A	Two pentadecathlons #28
	Pentadecathlon pair 31 xp15_075777757z4s4zdddz9f9	32	seventeenth	6	N/A	Two pentadecathlons #30
	Pentadecathlon pair 32 xp15_25w772w277w52y0eaeeeeae	34	ninth	6	N/A	Two pentadecathlons #19

Pseudo-pentadecathlon pairs

There exists at least three pseudo-oscillators involving a pentadecathlon cooperating with another to prevent a cell from being born due to overpopulation that would have remained dead anyway due to underpopulation.

Pentadecathlon pair envelope interactions

There are a multitude of oscillators which can be made up of a pentadecathlon's envelope intersecting, or even merely contacting, with that of another. These are generally given even less regard than pseudo-oscillators like the above, since there ultimately is no interaction between the two; they are generally only given attention due to apgsearch being unable to separate such cases.

Given the large span of possibilities and their low notability, no cases will be listed here.

Non-interacting pairs

An infinite number of pentadecathlon pairs exist in which there is absolutely no interaction between the two, but are nonetheless notable for other reactions, particularly for hassling (as in buddleia). A notable example of a non-interacting pentadecathlon pair, the PD-pair reflector, is capable of reflecting gliders 90 degrees. Other pentadecathlon pairs are capable of other reflections, with a 180-degree example seen in 6 bits.

Higher pentadecathlon combinations

It is possible to construct oscillators with an arbitrarily large pentadecathlon count via the pair interactions, as well as new interactions with pairs. Any such oscillators are still yet to occur naturally, although several have arisen from symmetric soups; oscillators containing five and six appear to be the highest known as of February 2022. The number of possible combinations for anything higher than two is still to be fully enumerated.