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A three dimensional plot includes a plot of a parabola in the xyplane and five lines that are parallel to the z-axis. The parabola is plotted in blue and opens toward the direction labeled as the x-axis. Four additional points (two with smaller
\(y\)-coordinate than the vertex and two with larger
\(y\)-coordinate than the vertex) are marked on the graph and plotted in green. Through each of these points is a line drawn parallel to the z-axis.