A simple reaction-diffusion model, known as the Gray-Scott model, exhibits a wide variety of spatio-temporal patterns in response to finite-amplitude perturbations. These patterns include regular hexagons, irregular steady patterns, chaotic spatio-temporal patterns, and time-dependent patterns such as spirals, phase turbulence, and stripes. The model is a variant of the Selkov model of glycolysis and is governed by two reactions: U + 2V → 3V and V → P. The resulting reaction-diffusion equations describe the dynamics of U and V, with diffusion coefficients D_u and D_v. The system size is 2.5 × 2.5, with D_u = 2 × 10^-5 and D_v = 10^-5. The boundary conditions are periodic, and the simulations use forward Euler integration of the finite difference equations. The spatial mesh consists of 256 × 256 grid points, with a time step of 1. The initial state is the trivial state (U = 1, V = 0), and a 20 × 20 mesh point area is perturbed to (U = 1/2, V = 1/4). The system is then integrated for 200,000 time steps, and an image is saved. The initial disturbance propagates outward from the central square, with a velocity of approximately 1 × 10^-4 space units per time unit. After the initial period, the system either enters a time-dependent state or an essentially steady state. The patterns observed include blue spots on a red or yellow background, with spots increasing in number until they fill the system. When spots reach a critical size, they divide into two. In some cases, spots decay into the uniform background. The patterns also include chaotic spatio-temporal patterns, with the largest Liapunov exponent for pattern ε being on the order of 1.5 × 10^-3, indicating chaotic behavior. The Gray-Scott model is relevant to biological systems, as it may explain sub-cellular chemical patterns in glycolysis. The study highlights the complexity of pattern formation in simple systems and the potential scientific interest of discovering new pattern formation phenomena.A simple reaction-diffusion model, known as the Gray-Scott model, exhibits a wide variety of spatio-temporal patterns in response to finite-amplitude perturbations. These patterns include regular hexagons, irregular steady patterns, chaotic spatio-temporal patterns, and time-dependent patterns such as spirals, phase turbulence, and stripes. The model is a variant of the Selkov model of glycolysis and is governed by two reactions: U + 2V → 3V and V → P. The resulting reaction-diffusion equations describe the dynamics of U and V, with diffusion coefficients D_u and D_v. The system size is 2.5 × 2.5, with D_u = 2 × 10^-5 and D_v = 10^-5. The boundary conditions are periodic, and the simulations use forward Euler integration of the finite difference equations. The spatial mesh consists of 256 × 256 grid points, with a time step of 1. The initial state is the trivial state (U = 1, V = 0), and a 20 × 20 mesh point area is perturbed to (U = 1/2, V = 1/4). The system is then integrated for 200,000 time steps, and an image is saved. The initial disturbance propagates outward from the central square, with a velocity of approximately 1 × 10^-4 space units per time unit. After the initial period, the system either enters a time-dependent state or an essentially steady state. The patterns observed include blue spots on a red or yellow background, with spots increasing in number until they fill the system. When spots reach a critical size, they divide into two. In some cases, spots decay into the uniform background. The patterns also include chaotic spatio-temporal patterns, with the largest Liapunov exponent for pattern ε being on the order of 1.5 × 10^-3, indicating chaotic behavior. The Gray-Scott model is relevant to biological systems, as it may explain sub-cellular chemical patterns in glycolysis. The study highlights the complexity of pattern formation in simple systems and the potential scientific interest of discovering new pattern formation phenomena.