Took me 11 days this month, to find a Wither Fort made of Blackstone Bricks that has a Magma Cube Spawner on the bottom level. In February I found one on the 1st day of the month less than 300 blocks away from my Nether Portal spawn point. Last Month it took me 14 days to find one. That is, not to say, the only thing I was doing. Mining gold and quartz killing pigmen etc. When I find the Magma Cube Spawner, I setup 4 Frog-light Farms using 4 hoppers each, a switch activated metal trap door on each end, glass and a chest. I then decorate my surroundings because I am going to be spending a lot of time there. I have somewhere close to 100k frog-lights. I have uploaded a small video of my Frog-light setup to my Minecraft Youtube channel.
