```r
plotUpToDay <- function(bear, day, ...){
	plot(bear$x, bear$y, type = "n", ...)
	b <- subset(bear, yday(datetime) <= day) 
	lines(b$x, b$y, col = "darkgrey")
	with(b[nrow(b),], points(x, y, pch = 21, bg = "yellow", col = "darkred", cex = 2))
	title(b$date[nrow(b)])
}
```