Настройка ПЛАВНОЙ анимации

.q1{ 
  position:absolute; 
  left:0px; 
  width:100px; 
  height:80px; 
  background:black; 
  animation: c1 5s linear infinite;  
} 
.q2{ 
  position:absolute; 
  left:110px; 
  width:100px; 
  height:100px; 
  background:black; 
  animation: c2 5s linear infinite; 
} 
  
@keyframes c1 { 
   15%{ 
       left:-252px; 
   } 
   15.1%{ 
        left:450px; 
   } 
 } 
@keyframes c2 { 
   15%{ 
       left:-252px; 
   } 
   15.1%{ 
        left:560px; 
   } 
   to{ 
       left:110px; 
   } 
}

<p class="q1"></p> 
<p class="q2"></p>