fun: Use R for Fun

## Letters "Happy New Year" rotating on the screen
## original code by Yixuan Qiu <yixuan.qiu@cos.name>
## URL: http://yixuan.cos.name/cn/wp-content/uploads/2009/12/2010.R
h.x = c(0.193, 0.295, 0.295, 0.703, 0.703, 0.804, 0.804, 0.703, 0.703,
    0.295, 0.295, 0.193, 0.193)
h.y = c(0.935, 0.935, 0.575, 0.575, 0.935, 0.935, 0.063, 0.063, 0.475,
    0.475, 0.063, 0.063, 0.935)
a1.x = c(0.433, 0.546, 0.865, 0.746, 0.656, 0.328, 0.242, 0.136)
a1.y = c(0.935, 0.935, 0.063, 0.063, 0.326, 0.326, 0.063, 0.063)
a2.x = c(0.488, 0.629, 0.355)
a2.y = c(0.841, 0.418, 0.418)
y.x = c(0.136, 0.259, 0.496, 0.734, 0.853, 0.543, 0.543, 0.441, 0.441)
y.y = c(0.935, 0.935, 0.523, 0.935, 0.935, 0.431, 0.063, 0.063, 0.427)
n.x = c(0.189, 0.295, 0.707, 0.707, 0.804, 0.804, 0.701, 0.287, 0.287, 0.189)
n.y = c(0.935, 0.935, 0.248, 0.935, 0.935, 0.063, 0.063, 0.747, 0.063, 0.063)
e.x = c(0.222, 0.787, 0.787, 0.324, 0.324, 0.757, 0.757, 0.324, 0.324,
    0.804, 0.804, 0.222)
e.y = c(0.935, 0.935, 0.834, 0.834, 0.564, 0.564, 0.464, 0.464, 0.163,
    0.163, 0.063, 0.063)
w.x = c(0, 0.099, 0.254, 0.439, 0.564, 0.738, 0.902, 1, 0.789, 0.687,
    0.5, 0.31, 0.205)
w.y = c(0.935, 0.935, 0.187, 0.935, 0.935, 0.189, 0.935, 0.935, 0.063,
    0.063, 0.826, 0.063, 0.063)
p.x = c(0.218, 0.56, 0.56, 0.56, 0.56, 0.32, 0.32, 0.218, 0.32, 0.32)
p.y = c(0.935, 0.933, 0.832, 0.518, 0.418, 0.418, 0.063, 0.063, 0.518, 0.834)
p.cir.th = seq(pi/2, -pi/2, length.out = 50)
p1.cir.x = 0.56 + 0.2575 * cos(p.cir.th)
p1.cir.y = 0.6755 + 0.2575 * sin(p.cir.th)
p2.cir.x = 0.56 + 0.157 * cos(p.cir.th)
p2.cir.y = 0.6755 + 0.157 * sin(p.cir.th)
p1.x = c(0.218, p1.cir.x, 0.32, 0.32, 0.218)
p1.y = c(0.935, p1.cir.y, 0.418, 0.063, 0.063)
p2.x = c(0.32, p2.cir.x, 0.32)
p2.y = c(0.832, p2.cir.y, 0.518)
r1.cir.th = seq(pi/2, -7/18 * pi, length.out = 50)
r2.cir.th = seq(pi/2, -pi/2, length.out = 50)
r1.cir.x = 0.578 + 0.243 * cos(r1.cir.th)
r1.cir.y = 0.6955 + 0.243 * sin(r1.cir.th)
r2.cir.x = 0.578 + 0.145 * cos(r2.cir.th)
r2.cir.y = 0.6955 + 0.145 * sin(r2.cir.th)
r1.x = c(0.191, r1.cir.x, 0.877, 0.75, 0.54, 0.297, 0.297, 0.191)
r1.y = c(0.937, r1.cir.y, 0.059, 0.059, 0.448, 0.448, 0.059, 0.059)
r2.x = c(0.297, r2.cir.x, 0.297)
r2.y = c(0.841, r2.cir.y, 0.55)
draw.ch = function(x1, y1, x2 = NULL, y2 = NULL, center.x,
    color, alpha, xscale) {
    rgb.col = col2rgb(color)/255
    x1 = x1 * xscale + center.x - 0.5 * xscale
    x2 = x2 * xscale + center.x - 0.5 * xscale
    polygon(x1, y1, col = rgb(rgb.col[1], rgb.col[2], rgb.col[3],
        alpha = alpha), border = NA)
    polygon(x2, y2, col = "black", border = NA)
}
x1 = list(h.x, a1.x, p1.x, p1.x, y.x, n.x, e.x, w.x,
    y.x, e.x, a1.x, r1.x)
y1 = list(h.y, a1.y, p1.y, p1.y, y.y, n.y, e.y, w.y,
    y.y, e.y, a1.y, r1.y)
x2 = list(NULL, a2.x, p2.x, p2.x, NULL, NULL, NULL,
    NULL, NULL, NULL, a2.x, r2.x)
y2 = list(NULL, a2.y, p2.y, p2.y, NULL, NULL, NULL,
    NULL, NULL, NULL, a2.y, r2.y)
th = seq(pi/6, 2 * pi, length.out = 12)
cols = rainbow(200)
par(bg = "black")
replicate(100, {
    for (j in 1:238) {
        th = th - pi/120
        center.x = 3 + 5 * cos(th)
        cols = c(cols[-1], cols[1])
        alpha = 0.1 + (50 * (1 - sin(th)))/100
        alpha = ifelse(alpha > 1, 1, alpha)
        xscale = -sin(th) * 1.2
        plot(1, xlim = c(-2, 8), ylim = c(-2.5, 3.5), type = "n", asp = 1)
        plot.order = (1:12)[order(xscale > 0)]
        for (k in 1:12) {
            i = plot.order[k]
            draw.ch(x1[[i]], y1[[i]], x2[[i]], y2[[i]], center.x[i],
                color = cols[k + 60 * ( i >= 6 & i <= 8 ) + 120 *
                    (i > 8)], alpha[i], xscale[i])
        }
        text(8, -2.5, "Yixuan @ 2009-12-31 (http://yixuan.cos.name)",
            adj = c(1, 0), col = "white", cex = 0.8)
        Sys.sleep(0.02)
    }
})