Small oozing potion slime farm

A slime and XP farm that does not use a slime chunk or a swamp. Snow golems are splashed with a potion of Oozing and dropped through trapdoors into water, where they die, and Oozing turns every death into slimes. Two dispensers and an observer drive the cycle, with shears in one of them. It is tiny, about a dozen items plus building blocks, and it works in any biome cold enough that snow golems do not melt. The catch is the input: every batch costs splash potions of Oozing, and neither the video nor the comments say where you are meant to get them in quantity.

• The snow golems dying is the point, not a fault. They die in the water and the Oozing effect leaves slimes behind.
• Build it anywhere except a hot biome. Desert, savanna and badlands melt the golems, which the creator confirms in a reply.
• Get the first trapdoor the right way round or the slimes go flying everywhere.
• If the golems do not drop through into the water, break the two trapdoors quickly.
• The dispenser has to face the observer directly or the shearing does not fire.
• One builder reports the observer refusing to rapid shear even with everything placed correctly, and gets no answer.