Well, I don't know why, but I have lately been more inclined to write for organ than piano. I suppose the tendency has always been present, but suppressed. I remember back in 1954, my friends would sometimes comment/complain that I tried to make the piano sound like an organ. I have some piano music under construction, but the organ insists on dominating my ideas. My most recent effort:
Changing Perspectives (Organ)
For ease of listening, I suggest that you concentrate on one voice, mostly the pedals, and listen to the relationships and interactions of the voices. It is very much linear. Harmony is certainly an element, but melodic relations are the main governing factor.
10 minutes of GPO organ, slightly modified by me. Four movements, approximately equal length.