It was one week ago that Akiyuky revealed the secret's behind his Basket Shooter GBC module.
Although, I have some doubts this could be named a GBC module, as I don't see any means to deliver the balls into the next module in the chain. However it could be seen as GBContraption in its essence. There is a ramp below the basket that can feed the balls into the next module in the chain. I think the ramp can be turned to make the balls returning to the shooters in this model, making it work in standalone module (another brilliant solution from Akiyuky).
No doubt this video reveals once more, the ingenious mind of his author, as we have been able to witness in all his previous modules.