No marks on a body meant that he or she was an obedient person. The slaves were required to dance or jump around to prove their limberness. Young, fair-skinned muttaloes, barely clothed and ready to be sold to brothel owners, were kept in private rooms (Foster). It was profitable to teach the slaves skills so that during the crop off-season they could be hired out to work. Although they were not being paid, some were doing more skilled work than poor whites were. The better behaved slaves were allowed to be carpenters, masons, bricklayers, or iron workers. The construction of bridges, streets, canals, railroad lines, public buildings, and private homes was made possible by using slave labor (Cowan and Maguire 5:44). Slaves had no rights. This was done to keep them from revolting against their masters or attaining too much power (Katz 3-5). They were not allowed to communicate with each other or have meetings of any sort. To leave the plantation, a worker was required to have a pass signed by the master and overseer. Slaves could not own property, although some masters authorized it. Knives, guns, or any kind of weapon was not allowed. Forced separation of family members was a constant, dreadful threat (Foster). "It was de saddes" thing dat ever happen to me," one slave recalls of the sale of her sister, whom she never saw again (qtd. in Foster). Blacks received harsher criminal sentencing than whites, regardless of the crime (Cowan and Maguire 5:17). Marriage between slaves was not legally recognized, but owners encouraged it because a more stable environment was created. Married couples with children were less likely to attempt escape. Unfortunately, there usually was not a suitable mate choice among the slaves, so most remained single (Starobin 7). Rebel slaves would recruit Indians, poor whites, and anti-slavery persons to attack all white men, women, and children (Starobin 123-26). These uprisings occurred with at least one major revolt per generation (Starobin 98).