This blue circle represents a node that has not yet been discovered by the algorithm. The node's name is shown in the center, and its current known shortest distance (e.g., N1.d) is displayed below.
When algorithm discovers node it turns red.
Solved nodes are green.
Edges look like arrows aiming from starting to end node. Each edge has it's weight c(N1, N2) above.
Edges that are currently in queue are gray.
When algorithm scans new edge and discovers new node they both turn red.
When algorithm scans new edge but do not discover new node, edge turns orange.