Each bench below runs a simplified model of one "dial" in physics. Pick a preset or drag the slider and the run restarts. The dashed ghost in each chart is our universe, so you can watch exactly where a modified universe parts ways with ours.
Early on, the pull of matter and the outward rush of expansion were almost perfectly balanced. This dial sets gravity's pull relative to that rush, starting when the universe was about 170,000 years old. Matter begins almost perfectly smooth (density ripples of 0.4%); gravity has to grow those ripples into stars before expansion thins everything out, or before gravity itself drags the whole universe back together.
Λ is a steady pressure built into empty space. Ours is tiny: it only took over about 5 billion years ago, long after galaxies formed. Naive quantum estimates put it up to 10120 times larger. A big positive Λ rips matter apart before it can clump; a big negative Λ pulls everything back into a crunch.
One second after the Big Bang there are about 5½ protons for every neutron. As the universe cools, a proton and neutron can bind into deuterium, which then fuses onward to helium. Deuterium is held together by only 2.2 MeV. Two protons (a "diproton") fall just short of being bound at all. Nudge the strong force and both facts change.
Inside a red giant, three helium nuclei fuse into carbon. Two of them first make beryllium-8, which falls apart in about 10−16 seconds, so a third has to arrive almost at once. That works because carbon-12 has an excited state, the "Hoyle state," 379 keV above the energy of three free helium nuclei: within reach of the star's heat. Some of the carbon then captures one more helium nucleus and becomes oxygen. Move the state and the star changes its temperature to compensate, which decides how much carbon survives.
α ≈ 1/137 sets the strength of electric forces. Inside every nucleus, protons repel one another and the strong force has to hold them together anyway; that same repulsion sets the neutron–proton mass gap and shifts the Hoyle state. Run the clock from the Big Bang to today and watch which elements are made and which survive. Chemistry itself changes smoothly (atoms shrink as 1/α, bonds strengthen as α²), so this bench looks for what breaks.
Times in the gravity and dark-energy benches are labelled using our universe's calibration (first stars ≈ 170 million years, galaxies ≈ 0.7 billion years, today ≈ 14 billion years). Further reading: Adams 2019, Oberhummer et al. 2000, Schlattl et al. 2004, Epelbaum et al. 2013, Huang, Adams & Grohs 2019.