def gradient(g_start, g_end, val)
    shex = g_start[1..-1].to_i(16)
    ehex = g_end[1..-1].to_i(16)
    r = shex >> 16
    g = shex >> 8 & 0xFF
    b = shex & 0xFF

    r += ((ehex >> 16)-r)*val
    g += ((ehex >> 8 & 0xFF)-g)*val
    b += ((ehex & 0xFF)-b)*val

    sprintf('#%02X%02X%02X', r.to_i, g.to_i, b.to_i)
end

def gradient_3pt(g_start, g_mid, g_end, val)
    val <= 0.50 ? gradient(g_start, g_mid, val*2) : gradient(g_mid, g_end, 2*val - 1)
end

def rand_range(lower, upper)
	lower + (upper-lower)*rand(0)
end

white_color = gradient_3pt('#FF0000', '#FFFFFF', '#0066CC', rand_range(0.40, 0.60))
purple_color = gradient('#FF0000', '#0066CC', rand_range(0.40, 0.60))