What lava stream layout will disable a blaze spawner?

Solution 1:

These pictures look a bit old - on previous versions the spawning area was 8x8x3 centered on the edge of the spawner.

In current versions it is 9x9x3 centered around the center of the spawner. Blazes need light level of 11 or less to be able to spawn. The idea in all of the above pictures is to maintain light level of 12 or more inside the spawning area. The light decreases by one with each block traveled. Glowstone (and lava) are light level 15, the adjacent blocks are light level 14 etc.

Armed with the above, we can now construct the following:

Lava dispensers are at the 4 marked locations and are facing down. The spawner is in the center. Lava will make a plus sign when flowing form a downward-facing dispenser, that is why there is a plus sign of light level 15 and then on the rest of the blocks light level decreases but is still above 11.