Four small strokes lined up under a character — that's the cooking-fire cue. 灬 marks heat, flames, roasting, and shining light. The pedagogical name sìdiǎndǐ literally means 'four-dot bottom'. Never written alone; the standalone form is 火.
history
灬 is the calligraphic flattening of 火. The standing flame of the full fire glyph spread into four short licks so the radical could fit beneath another component without crowding it. The dots visually echo embers scattered under a pot.
