Meiosis doesn't just halve chromosome count — it shuffles the deck twice before dealing. Independent assortment alone creates over 8 million possible combinations from one parent's chromosomes, and that's before crossing over or fertilisation. Drag the slider to watch chromosomes independently assort into gametes.
During prophase I, homologous chromosomes pair up and physically swap DNA segments at chiasmata — the crossover points. A single chromosome might contain your dad's eye-colour gene but your mum's blood-type gene, even though both came from the same original chromosome. This recombination happens before the chromosomes even line up for independent assortment, so every chromosome entering a gamete is already a unique mosaic. Crossing over typically occurs multiple times per chromosome pair, which is why the variation from this mechanism alone is effectively infinite — siblings inheriting the "same" chromosome from a parent are actually getting different recombinant versions every time.
Meiosis generates variation through independent assortment (223 combinations from random chromosome sorting), crossing over (segment swaps during prophase I), and random fertilisation (any sperm meeting any egg).