Fan and Tubular Growth Promotion

[Matt Jackson]

Hi everyone,
I am looking to promote tubular and fan like growth in Physarum Polycephalum in 2 separate dishes (1 with tubes, the other with fans). I think to promote tubular growth, I will have a medium with low nutrient content in a petri dish scattered with porridge oats or something like that (any recommendations for this medium?). However what kind of medium could be evenly distributed across a dish that would promote the alternative fan like growth of the slime mould? Could it just be agar or something a bit stronger, to let the mould know that it's found something?

Thanks very much