<｜begin▁of▁sentence｜>### Instruction:
As a grant writer, I often collaborate with organizations seeking funding for crucial projects. Recently, I was asked to research and submit grant proposals for a nonprofit organization focusing on environmental education. One key aspect of the proposal involves visualizing the impact of their programs through a tree graph with 3 children per node and a depth of 2. Additionally, the organization aims to highlight the significant influence of a particular vertex by representing it as a blue circle with a size of 10 at specific coordinates on the graph. This visualization will play a pivotal role in illustrating the reach and potential of their initiatives to potential funders and stakeholders in a compelling and interactive manner.
### Response:
import igraph as ig
import plotly.graph_objects as go
from igraph.drawing.plotly_draw import PlotlyGraphDrawer

class CustomPlotlyVerticesDrawer(PlotlyGraphDrawer):
    def draw_vertex(self, visual_vertex, vertex, point, coords):
        # Assume visual_vertex contains color and size info
        color = visual_vertex['color']
        size = visual_vertex['size']
        # Use Plotly to draw the vertex
        self.result.add_trace(go.Scatter(x=[coords[0]], y=[coords[1]],
                                         mode='markers',
                                         marker=dict(color=color, size=size)))

# Mock data for illustration
visual_vertex_info = {'color': 'blue', 'size': 10}
vertex_id = 0
vertex_position = (1, 2)

g = ig.Graph.Tree(3, 2)
layout = g.layout('rt')

drawer = CustomPlotlyVerticesDrawer()
drawer.prepare_plot(g, layout)
drawer.draw_vertex(visual_vertex_info, vertex_id, None, vertex_position)

# The plot is prepared and can be displayed with Plotly
#drawer.show()  # Uncomment to display the plot
<|EOT|>
