CEDAR RAPIDS — For eight minutes and 46 seconds Saturday, thousands of people lay down on downtown’s First Avenue — their hands behind their backs, blocking traffic and making their voices heard.“Say his name!” they chanted, invoking the name of George Floyd, the black Minneapolis man killed by a white police officer on May 25 who knelt on his neck for nearly nine minutesLying in the street, protesters shouted his final words, “I can’t breathe,” as a protester counted off the seconds through a megaphone.They said his name — George Floyd — but they also said the peaceful protest Saturday evening was about more than one person.“It’s about everyone who lost their lives because of racism and hatred,” Louise Johnson said at a rally in Greene Square before the march.