Not entirely sure what you mean by “shapes”, but you can completely customize the look of your accordion using CSS. The CSS classes you’ll want to use are:
.c-accordion__item {} /* The accordion item container */
.c-accordion__item.is-open {} /* is-open is added to open accordion items */
.c-accordion__item.is-read {} /* is-read is added to accordion items that have been opened at least once */
.c-accordion__title {} /* An accordion item title */
.c-accordion__title--button {} /* An accordion item title that is using a <code><button></code> tag */
.c-accordion__title:hover {} /* To modify the style when hovering over an accordion item title */
.c-accordion__title:focus {} /* To modify the style when an accordion item title currently has broswer focus */
.c-accordion__content {} /* An accordion item content container */
