Block Diagram disable arrow heads?

[ryanworsley]

Hi,

Totally new to Mermaid, but I'm stumped using block-beta, I'd simply like to get rid of the arrowheads rendered by

block-beta
  columns 7
  01(("α")) space:2 11((" ")) space:2 21((" "))
  02(("β")) space:2 12((" ")) space:2 22((" "))
  03(("γ")) space:2 13((" ")) space:2 23((" "))

  01 --- 11
  01 --- 12
  02 --- 11
  02 --- 12
  02 --- 13
  03 --- 13

  11 --- 21
  11 --- 22
  12 --- 22
  12 --- 23
  13 --- 22
  13 --- 23

which looks like this and is very much cluttered by the arrow heads

Very much open to any suggestions to make this clearer? Ultimately there will be 4/5 (maybe more!) layers of nodes running left to right as the diagram evolves.

Cheers in advance!