Masonry

Many workmen 
Built a huge ball of masonry 
Upon a mountain-top. 
Then they went to the valley below, 
And turned to behold their work. 
"It is grand," they said; 
They loved the thing. 
Of a sudden, it moved: 
It came upon them swiftly; 
It crushed them all to blood. 
But some had opportunity to squeal.