circle_illusion.jl

using ColorSchemes
using Javis

N = 6  # Number of dots
radius = 20  # Radius of each dot
colors = ColorSchemes.rainbow1  # Color palette
speed = 10  # Degrees per frame

function draw_circle(frame, i, radius, speed)
    # Angle of the direction vector for the dot
    θ = (π/N)*i
    # Parameterize the dot's position in terms
    # of the frame index
    ρ = (frame % 360)*(speed/360)
    r = 230cos(θ + ρ)
    v = Point(cos(θ), sin(θ))
    position = r*v
    # Set the color of the dot
    color_idx = Int(floor(length(colors) / N)) * i
    sethue(colors[color_idx])
    # Draw the dot
    circle(position, radius, :fill)
end

video = Video(500, 500)
frames = 226

Background(1:frames, (args...) -> background("black"))

for i in 1:N
    Object(1:frames, (_, _, frame) -> draw_circle(frame, i, radius, speed))
end

render(video, pathname="circles.gif")