What did thaddeus kosciusko do? what did casimir pulaski do?

They were both from Poland and they both fought in US Independence War. Kościuszko was fighting more in norther part of US, he was famous for building forts. Pułaski fought more on south US, he created first American cavalry. They are still national heroes in Poland.

Thaddeus Kosciuszko was a Polish engineer who came to America in 1776 to provide his services to aid America in attain independence from Britain. He helped strengthen the Fort Mercer Philadelphia waterfront and became the chief engineer of West Point (NY). West Point became known as the "American Gibraltar" because the British couldn't penetrate it.

  Casimir Pulaski was a military commander and soldier born in Warsaw, Poland. He became known by the moniker "The Father of American Cavalry". In 1776 he came to America to help fight against the British to gain independence. Due to his great service, he was promoted to Brigadier General in command of cavalry by U.S. congress.