This would be a struggle, since you would have to manage raycasts in multiple directions... I would say your best option is to use a loopcast or circle spell to make a pseudo-sphere, which is basically a sphere that isn't really a sphere. You could manage that by doing some weird vector calculations, but that make block placements would also cost a stupid amount of energy and take a while either way. I wouldn't recommend it to be honest. It is possible though.