"corner" <-
function(x, corner='tlffff', n=rep(6, length(corner)))
{
	# placed in the public domain 2002 
	# Patrick Burns patrick@burns-stat.com
	if(length(corner) != 1) stop('corner must be a single string')
	dx <- dim(x)
	ldx <- length(dx)
	if(ldx < 2) {
		if(substring(corner, 1,1) == 't')
			return(head(x, n=n[1])) 
		else 
			return(tail(x, n=n[1]))
	}

	clen <- nchar(corner)
	if(clen < ldx) {
		if(clen ==0) {
			corner <- paste('tl', paste(rep('f', ldx - 2), 
				collapse=''), sep='')
		} else if(clen == 1)
			corner <- paste(corner, 'l', paste(rep('f', ldx - 1), 
				collapse=''), sep='')
		else
			corner <- paste(corner, paste(rep('f', ldx - clen), 
				collapse=''), sep='')
	}
	corner <- substring(corner, 1:ldx, 1:ldx)
	n <- rep(n, length=ldx)

	if(corner[1] == 't') 
		rsub <- 1:min(n[1], dx[1]) 
	else 
  		rsub <- seq(to=dx[1], length=min(n[1], dx[1]))

	if(corner[2] == 'l') 
		csub <- 1:min(n[2], dx[2]) 
	else
  		csub <- seq(to=dx[2], length=min(n[2], dx[2]))

	if(ldx == 2) {
  		return(x[rsub, csub, drop=FALSE])
	} 

	subv <- vector('list', ldx + 1)
	subv[[1]] <- rsub; subv[[2]] <- csub
	for(i in 3:ldx) {
 		if(corner[i] == 'f') 
			subv[[i]] <- 1:min(n[i], dx[i]) 
		else
   			subv[[i]] <- seq(to=dx[i], length=min(n[i], dx[i]))
	}

	names(subv) <- c(rep('', ldx), 'drop')
	subv[[ldx + 1]] <- FALSE
	do.call('[', c(list(x), subv))
}