Block Propagation Grid

The SNP spec specifies that nodes need to announce their blocks only to specific peers - not to the whole network. Our interpretation of the SNP spec leads to the following grid for block propagation:

There are three grids; previous, current and future validator set.
As simplification it uses just eight instead of 31 as grid size. One validator is selected in red, propagating to its first order peers in red. The second order propagations are in green. The third order propagations are all nodes.

Example

For the validator with index 32 (grid coordinate (1, 1)), this would mean that they are propagating to the following other validator coordinates on the same epoch:

[{0, 1}, {2, 1}, {3, 1}, {4, 1}, {5, 1}, {6, 1}, {7, 1}, {8, 1}, {9, 1}, {10, 1}, {11, 1}, {12, 1}, {13, 1}, {14, 1}, {15, 1}, {16, 1}, {17, 1}, {18, 1}, {19, 1}, {20, 1}, {21, 1}, {22, 1}, {23, 1}, {24, 1}, {25, 1}, {26, 1}, {27, 1}, {28, 1}, {29, 1}, {30, 1}, {1, 0}, {1, 2}, {1, 3}, {1, 4}, {1, 5}, {1, 6}, {1, 7}, {1, 8}, {1, 9}, {1, 10}, {1, 11}, {1, 12}, {1, 13}, {1, 14}, {1, 15}, {1, 16}, {1, 17}, {1, 18}, {1, 19}, {1, 20}, {1, 21}, {1, 22}, {1, 23}, {1, 24}, {1, 25}, {1, 26}, {1, 27}, {1, 28}, {1, 29}, {1, 30}]

Translating to the following indices:

[1, 63, 94, 125, 156, 187, 218, 249, 280, 311, 342, 373, 404, 435, 466, 497, 528, 559, 590, 621, 652, 683, 714, 745, 776, 807, 838, 869, 900, 931, 31, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61]

Additionally their are also propagating to the same indices in the previous and future epoch.