import java.awt.*
import javax.swing.*

fun main() {
    SwingUtilities.invokeLater {
        val panel  = object: JPanel() {
            override fun paintComponent(g: Graphics) {
	        super.paintComponent(g)
		val scale = 4;
		for (i in 0..63) {
		    g.setColor(Color(i * 4, 0, 255 - i * 4))
		    g.fillRect(i * scale, 0, scale, 40) 
                }
            }
        }
        panel.setPreferredSize(Dimension(256, 40))  
    
    	val frame = JFrame("Gradation")
	frame.add(panel)
	frame.pack()
    	frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE)
    	frame.setVisible(true)
    }
}