demo-container { display: block; padding: 25px 10px 10px; border-radius: 4px; width: 200px; height: 160px; border: 1px solid rgb(128, 128, 128); margin-bottom: 10px; background-image: linear-gradient(transparent, transparent 49%, black 50%, black 51%, transparent 52%); }
demo-object { display: block; background-color: rgb(255, 0, 0); offset-path: path("M 20 20 C 20 100 150 0 150 100"); animation: 3000ms ease-in-out 0s infinite alternate none running move; width: 40px; height: 40px; }
.element {offset-position: 1% 1%;}

@keyframes move {
0%, 20% { offset-distance: 0%; }
80%, 100% { offset-distance: 100%; }
}