list manipulation - Linearly change the step size in a table

I am trying to create a table of points, where the size of the step would change linearly from a certain value to another. Bellow is a simple code to demonstrate a table of points with a constant step in X and Y direction.

MasterMesh=Flatten[Table[{XX , YY, 0}, {XX, -1/2, 1/2, 0.2}, {YY, -1/2, 1/2, 0.2}], 1];
ListPointPlot3D[MasterMesh]

My goal would ultimately be, to create a raster of point that is something like shown in the figure bellow (drawn clumsily), where the distances between the new points (marked red bellow) are supposed to change linearly in a way that L1:L2:L3:L4:L5=1:2:3:4:5.

Any help will be much appreciated!

Answer

g1 = Prepend[Accumulate@Range[5], 0]
(* {0, 1, 3, 6, 10, 15} *)

g2 = Prepend[Accumulate@Reverse@Range[5], 0]
(* {0, 5, 9, 12, 14, 15} *)

Join @@ MapIndexed[{First[#2], #1, 0} &,
   Subdivide[g1, g2, 5],

   {2}
   ] // ListPointPlot3D