How to produce a DLA Cluster Image

I am using Matlab to run a simulation that can produce a DLA/cluster/aggregate image ( https://en.wikipedia.org/wiki/File:Of7_p0001_15h.jpg - this sort of image for reference).

I started with a random walk where each particle that undergoes the walk starts from a Lattice Boundary and if it come into contact with a 'seed' particle at the centre of the lattice the particle will stop walking and 'attach' itself to the seed. This continues until all the particles have ran and an image with fractal like properties is formed.

for a = 1:N
  [x,y,z] = DLARandWalk(n,dt,D,b);
  plot3(x,y,z,'--')
  hold on
end

DLARandWalk is the walk function per particle (N the number of particles) and the inputs are n, number of steps, dt, change in time per step, D, a diffusion constant that determines step size and b which represents the lattice boundary conditions.

My question is, what can I use to enable this aggregation? I have tried some logicals, an if loop if the [x,y,z] components match but it hasn't worked. Thanks in advance,