convert from space separated to matrix (wolfram alpha format)

gistfile1.rb

l = gets
num_list = l.split(/\s/)
n = Math.sqrt(num_list.size).to_i

print '{'
n.times {
	print '{'
	(n-1).times {
		print "%s, " % num_list.shift
	}
	print "%s" % num_list.shift
	print '}'
	print "," if num_list.size > 0
}
print '}