По запросу: "triangular number triangle" найдено 106 иконок.

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phone
polygon
ionicons-v5-a
Equation Icon This is shape (source) for Clarity vector icon theme for gtk Equation Icon This is shape (source) for Clarity vector icon theme for gtk Jakub Jankiewicz Jakub Jankiewicz 2010 image/svg+xml
unlock-filled
Phone Created with Sketch.
https://www.svgrepo.com/show/446398/n-a.svg