Card from a student at West Allegheny Middle School in Imperial, Pa. The front features a hand-colored illustration of a turtle with floral and geometric motifs. The back contains a handwritten note, as well as the stock signature: "From your friends at West Allegheny Middle School."

Printed tag with a photograph of David Rosenthal. The tag reads: "In Memory of David Rosenthal." Creasing and staining due to exposure to the elements at the Wilkins memorial.

Square card with white and yellow text against blue background. Card reads, "Mitzvah4Pittsburgh. Some spread darkness. We spread light. Choose a good deed. Choose a Mitzvah. Add light to the world," followed by four options and a place for respondents to list their name and email address. Some names and email addresses have been redacted for privacy.

Card from a congregant at the Holy Angels Parish. The front cover contains a stock illustration of seven children holding hands around a table with a large goblet and loaf of braided bread, and seven doves. The illustration is labeled: "We are people of God's peace." The inside reads: "Dear Tree of Life member. You are all in our thoughts and prayers. Holy Angels\CCD. Jason [last name redacted]." Due to water exposure at the memorial site, the ink on this card has partially lifted.

Square card with white and yellow text against blue background. Card reads, "Mitzvah4Pittsburgh. Some spread darkness. We spread light. Choose a good deed. Choose a Mitzvah. Add light to the world," followed by four options and a place for respondents to list their name and email address. Some names and email addresses have been redacted for privacy.

Post-it note with handwritten message in blue ink. The message reads: "Full recovery for all injured."

Post-it note with handwritten message in black ink. The message reads: "Z"L."

Post-it note with handwritten message in black ink. The note is written in Hebrew and English. Translated into English, the message reads: "All of Israel are connected to one another. We are with you!"

Post-it note with handwritten message in blue marker. The message reads: "When there is dark be the one who turns on the light."

Handwritten "Prayer of St. Francis" written in black ink on white paper, glued to cardboard. Warping due to exposure to the elements at the Wilkins memorial.

Note from a member of The Church at Severn Run in Severn, Maryland. The note is enclosed in an envelope with church letterhead, reading: "The Church at Severn Run: Love Well, Live Jesus, Believe Big!" The note inside reads: "You are loved by GOD and by ME. [Signature illegible]." The church's contact information is included on the back of the envelope.

Handwritten note written in black ink expressing the author's wish that the site of the October 27 attack and its memory become a source of love and strength. Tearing and staining due to exposure to the elements at the Wilkins memorial.

Folded card with marker illustration. Cover features illustration of tree with ladder. Interior reads, "We are with you at this sorrowful time. The Beth Chai Congregation of Greater Washington." Back cover reads "I hope you feel better. P.S. We will donate $ to you" with two five-pointed stars.

Handmade card in colored pencil on paper. The outside features a series of staples running down the side and two hole punches. Cream-colored yarn is tied in a bow around the left-hand hole. From right to left, the inside reads, in Hebrew: "Zachor" (remember) and "Love, Cat Dog. Me and family are so sorry." Assorted hearts appear on the right flap; a group of multicolored blocks with a heart-shaped cat or dog face on top appears on the left. The back is signed, on the lower center: "From Aviva and Shosie."

Square card with white and yellow text against blue background. Card reads, "Mitzvah4Pittsburgh. Some spread darkness. We spread light. Choose a good deed. Choose a Mitzvah. Add light to the world," followed by four options and a place for respondents to list their name and email address. Some names and email addresses have been redacted for privacy.

Handwritten card from a student at Goddard Middle School in Littleton, Co. The front cover reads: "F.e.a.r. has two meanings- Forget everything and run OR Face everything and rise. The choice is yours." A star of David and cartoonish illustration of a smiling boy wearing a red baseball cap appear below; a shining sun in the upper right corner. The inside reads: "Dear Rabbi Jeffrey Myers, We are sorry for your loss and we hope you are recovering well. -Aiden G. Littleton, Colorado." Spelling errors corrected for clarity.

Post-it note with handwritten message in black marker. The message reads: "The neighborhood is with you." A heart appears below.

Card with a peacock on the front cover. The card reads: "A Catholic who loves all Jewish people! A friend, a neighbor, she loves you."

Card from a student at West Allegheny Middle School in Imperial, Pa. The front features a hand-colored illustration of the words: "You Got This" surrounded by a border with a grapevine pattern. The back contains a handwritten note, as well as the stock signature: "From your friends at West Allegheny Middle School."